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Navarro-Mendoza MI, Pérez-Arques C, Parker J, Xu Z, Kelly S, Heitman J. Alternative ergosterol biosynthetic pathways confer antifungal drug resistance in the human pathogens within the Mucor species complex. mBio 2024; 15:e0166124. [PMID: 38980037 PMCID: PMC11323496 DOI: 10.1128/mbio.01661-24] [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: 06/03/2024] [Accepted: 06/18/2024] [Indexed: 07/10/2024] Open
Abstract
Mucormycoses are emerging fungal infections caused by a variety of heterogeneous species within the Mucorales order. Among the Mucor species complex, Mucor circinelloides is the most frequently isolated pathogen in mucormycosis patients and despite its clinical significance, there is an absence of established genome manipulation techniques to conduct molecular pathogenesis studies. In this study, we generated a spontaneous uracil auxotrophic strain and developed a genetic transformation procedure to analyze molecular mechanisms conferring antifungal drug resistance. With this new model, phenotypic analyses of gene deletion mutants were conducted to define Erg3 and Erg6a as key biosynthetic enzymes in the M. circinelloides ergosterol pathway. Erg3 is a C-5 sterol desaturase involved in growth, sporulation, virulence, and azole susceptibility. In other fungal pathogens, erg3 mutations confer azole resistance because Erg3 catalyzes the production of a toxic diol upon azole exposure. Surprisingly, M. circinelloides produces only trace amounts of this toxic diol and yet, it is still susceptible to posaconazole and isavuconazole due to alterations in membrane sterol composition. These alterations are severely aggravated by erg3Δ mutations, resulting in ergosterol depletion and, consequently, hypersusceptibility to azoles. We also identified Erg6a as the main C-24 sterol methyltransferase, whose activity may be partially rescued by the paralogs Erg6b and Erg6c. Loss of Erg6a function diverts ergosterol synthesis to the production of cholesta-type sterols, resulting in resistance to amphotericin B. Our findings suggest that mutations or epimutations causing loss of Erg6 function may arise during human infections, resulting in antifungal drug resistance to first-line treatments against mucormycosis. IMPORTANCE The Mucor species complex comprises a variety of opportunistic pathogens known to cause mucormycosis, a potentially lethal fungal infection with limited therapeutic options. The only effective first-line treatments against mucormycosis consist of liposomal formulations of amphotericin B and the triazoles posaconazole and isavuconazole, all of which target components within the ergosterol biosynthetic pathway. This study uncovered M. circinelloides Erg3 and Erg6a as key enzymes to produce ergosterol, a vital constituent of fungal membranes. Absence of any of those enzymes leads to decreased ergosterol and consequently, resistance to ergosterol-binding polyenes such as amphotericin B. Particularly, losing Erg6a function poses a higher threat as the ergosterol pathway is channeled into alternative sterols similar to cholesterol, which maintain membrane permeability. As a result, erg6a mutants survive within the host and disseminate the infection, indicating that Erg6a deficiency may arise during human infections and confer resistance to the most effective treatment against mucormycoses.
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Affiliation(s)
- María Isabel Navarro-Mendoza
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, North Carolina, USA
| | - Carlos Pérez-Arques
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, North Carolina, USA
| | - Josie Parker
- Molecular Biosciences Division, School of Biosciences, Cardiff University, Cardiff, Wales, United Kingdom
| | - Ziyan Xu
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, North Carolina, USA
| | - Steven Kelly
- Institute of Life Science, Swansea University Medical School, Swansea, Wales, United Kingdom
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, North Carolina, USA
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2
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Li N, Bowling J, de Hoog S, Aneke CI, Youn JH, Shahegh S, Cuellar-Rodriguez J, Kanakry CG, Rodriguez Pena M, Ahmed SA, Al-Hatmi AMS, Tolooe A, Walther G, Kwon-Chung KJ, Kang Y, Lee HB, Seyedmousavi A. Mucor germinans, a novel dimorphic species resembling Paracoccidioides in a clinical sample: questions on ecological strategy. mBio 2024; 15:e0014424. [PMID: 38953355 PMCID: PMC11323738 DOI: 10.1128/mbio.00144-24] [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: 01/16/2024] [Accepted: 05/30/2024] [Indexed: 07/04/2024] Open
Abstract
Dimorphism is known among the etiologic agents of endemic mycoses as well as in filamentous Mucorales. Under appropriate thermal conditions, mononuclear yeast forms alternate with multi-nucleate hyphae. Here, we describe a dimorphic mucoralean fungus obtained from the sputum of a patient with Burkitt lymphoma and ongoing graft-versus-host reactions. The fungus is described as Mucor germinans sp. nov. Laboratory studies were performed to simulate temperature-dependent dimorphism, with two environmental strains Mucor circinelloides and Mucor kunryangriensis as controls. Both strains could be induced to form multinucleate arthrospores and subsequent yeast-like cells in vitro. Multilateral yeast cells emerge in all three Mucor species at elevated temperatures. This morphological transformation appears to occur at body temperature since the yeast-like cells were observed in the lungs of our immunocompromised patient. The microscopic appearance of the yeast-like cells in the clinical samples is easily confused with that of Paracoccidioides. The ecological role of yeast forms in Mucorales is discussed.IMPORTANCEMucormycosis is a devastating disease with high morbidity and mortality in susceptible patients. Accurate diagnosis is required for timely clinical management since antifungal susceptibility differs between species. Irregular hyphal elements are usually taken as the hallmark of mucormycosis, but here, we show that some species may also produce yeast-like cells, potentially being mistaken for Candida or Paracoccidioides. We demonstrate that the dimorphic transition is common in Mucor species and can be driven by many factors. The multi-nucleate yeast-like cells provide an effective parameter to distinguish mucoralean infections from similar yeast-like species in clinical samples.
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Affiliation(s)
- Na Li
- Key Laboratory of Environmental Pollution Monitoring and Disease Control, Ministry of Education of Guizhou, Guizhou Medical University, Guiyang, China
- Key Laboratory of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Guizhou Medical University, Guiyang, China
- RadboudUMC-CWZ Center for Expertise in Mycology, Nijmegen, the Netherlands
| | - Jennifer Bowling
- Microbiology Service, Department of Laboratory Medicine, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Sybren de Hoog
- Key Laboratory of Environmental Pollution Monitoring and Disease Control, Ministry of Education of Guizhou, Guizhou Medical University, Guiyang, China
- Key Laboratory of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Guizhou Medical University, Guiyang, China
- RadboudUMC-CWZ Center for Expertise in Mycology, Nijmegen, the Netherlands
| | - Chioma I. Aneke
- Microbiology Service, Department of Laboratory Medicine, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Jung-Ho Youn
- Microbiology Service, Department of Laboratory Medicine, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Sherin Shahegh
- Microbiology Service, Department of Laboratory Medicine, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Jennifer Cuellar-Rodriguez
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Christopher G. Kanakry
- Center for Immuno-Oncology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Maria Rodriguez Pena
- Laboratory of Pathology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Sarah A. Ahmed
- RadboudUMC-CWZ Center for Expertise in Mycology, Nijmegen, the Netherlands
| | | | - Ali Tolooe
- Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada
- Vet Veterinary Diagnostic Laboratory, Tehran, Iran
| | - Grit Walther
- German National Reference Center for Invasive Fungal Infections, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knöll Institute, Jena, Germany
| | - Kyung J. Kwon-Chung
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Yingqian Kang
- Key Laboratory of Environmental Pollution Monitoring and Disease Control, Ministry of Education of Guizhou, Guizhou Medical University, Guiyang, China
- Key Laboratory of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Guizhou Medical University, Guiyang, China
- Institution of One Health Research, Guizhou Medical University, Guiyang, China.
| | - Hyang Burm Lee
- Environmental Microbiology Laboratory, Department of Agricultural Biological Chemistry, College of Agriculture and Life Sciences, Chonnam National University, Gwangju, South Korea
| | - Amir Seyedmousavi
- Microbiology Service, Department of Laboratory Medicine, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
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3
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Sousa IS, Tavares LFS, Silva BA, Moreno DSA, Alviano CS, Santos ALS, Kneipp LF. Calcineurin activity in Fonsecaea pedrosoi: tacrolimus and cyclosporine A inhibited conidia growth, filamentation and showed synergism with itraconazole. Braz J Microbiol 2024:10.1007/s42770-024-01463-2. [PMID: 39044105 DOI: 10.1007/s42770-024-01463-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Accepted: 07/11/2024] [Indexed: 07/25/2024] Open
Abstract
Fonsecaea pedrosoi is a melanized fungus that causes chromoblastomycosis (CBM), a tropical neglected disease responsible for chronic and disability-related subcutaneous mycosis. Given the challenging nature of CBM treatment, the study of new targets and novel bioactive drugs capable of improving patient life quality is urgent. In the present work, we detected a calcineurin activity in F. pedrosoi conidial form, employing primarily colorimetric, immunoblotting and flow cytometry assays. Our findings reveal that the calcineurin activity of F. pedrosoi was stimulated by Ca2+/calmodulin, inhibited by EGTA and specific inhibitors, such as tacrolimus (FK506) and cyclosporine A (CsA), and proved to be insensitive to okadaic acid. In addition, FK506 and CsA were able to affect the cellular viability and the fungal proliferation. This effect was corroborated by transmission electron microscopy that showed both calcineurin inhibitors promoted profound changes in the ultrastructure of conidia, causing mainly cytoplasm condensation and intense vacuolization that are clear indication of cell death. Our data indicated that FK506 exhibited the highest effectiveness, with a minimum inhibitory concentration (MIC) of 3.12 mg/L, whereas CsA required 15.6 mg/L to inhibit 100% of conidial growth. Interestingly, when both were combined with itraconazole, they demonstrated anti-F. pedrosoi activity, exhibiting a synergistic effect. Moreover, the fungal filamentation was affected after treatment with both calcineurin inhibitors. These data corroborate with other calcineurin studies in fungal cells and open up further discussions aiming to establish the role of this enzyme as a potential target for antifungal therapy against CBM infections.
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Affiliation(s)
- Ingrid S Sousa
- Laboratório de Taxonomia, Bioquímica e Bioprospecção de Fungos (LTBBF), Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, 21040-900, Brazil
| | - Lucilene F S Tavares
- Laboratório de Taxonomia, Bioquímica e Bioprospecção de Fungos (LTBBF), Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, 21040-900, Brazil
| | - Bianca A Silva
- Laboratório de Estudos Avançados de Microrganismos Emergentes e Resistentes (LEAMER), Instituto de Microbiologia Paulo de Góes (IMPG), Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, 21941-901, Brazil
| | - Daniela S A Moreno
- Laboratório de Estrutura de Microrganismos, IMPG, UFRJ, Rio de Janeiro, 21941-902, Brazil
| | - Celuta S Alviano
- Laboratório de Estrutura de Microrganismos, IMPG, UFRJ, Rio de Janeiro, 21941-902, Brazil
| | - André L S Santos
- Laboratório de Estudos Avançados de Microrganismos Emergentes e Resistentes (LEAMER), Instituto de Microbiologia Paulo de Góes (IMPG), Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, 21941-901, Brazil
- Rede Micologia RJ, Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ), Rio de Janeiro, 21941-901, Brazil
| | - Lucimar F Kneipp
- Laboratório de Taxonomia, Bioquímica e Bioprospecção de Fungos (LTBBF), Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, 21040-900, Brazil.
- Rede Micologia RJ, Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ), Rio de Janeiro, 21941-901, Brazil.
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4
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Lax C, Mondo SJ, Osorio-Concepción M, Muszewska A, Corrochano-Luque M, Gutiérrez G, Riley R, Lipzen A, Guo J, Hundley H, Amirebrahimi M, Ng V, Lorenzo-Gutiérrez D, Binder U, Yang J, Song Y, Cánovas D, Navarro E, Freitag M, Gabaldón T, Grigoriev IV, Corrochano LM, Nicolás FE, Garre V. Symmetric and asymmetric DNA N6-adenine methylation regulates different biological responses in Mucorales. Nat Commun 2024; 15:6066. [PMID: 39025853 PMCID: PMC11258239 DOI: 10.1038/s41467-024-50365-2] [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: 01/30/2024] [Accepted: 07/05/2024] [Indexed: 07/20/2024] Open
Abstract
DNA N6-adenine methylation (6mA) has recently gained importance as an epigenetic modification in eukaryotes. Its function in lineages with high levels, such as early-diverging fungi (EDF), is of particular interest. Here, we investigated the biological significance and evolutionary implications of 6mA in EDF, which exhibit divergent evolutionary patterns in 6mA usage. The analysis of two Mucorales species displaying extreme 6mA usage reveals that species with high 6mA levels show symmetric methylation enriched in highly expressed genes. In contrast, species with low 6mA levels show mostly asymmetric 6mA. Interestingly, transcriptomic regulation throughout development and in response to environmental cues is associated with changes in the 6mA landscape. Furthermore, we identify an EDF-specific methyltransferase, likely originated from endosymbiotic bacteria, as responsible for asymmetric methylation, while an MTA-70 methylation complex performs symmetric methylation. The distinct phenotypes observed in the corresponding mutants reinforced the critical role of both types of 6mA in EDF.
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Affiliation(s)
- Carlos Lax
- Departamento de Genética y Microbiología, Facultad de Biología, Universidad de Murcia, Murcia, Spain
| | - Stephen J Mondo
- U.S. Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Agricultural Biology, Colorado State University, Fort Collins, CO, 80523, USA
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Macario Osorio-Concepción
- Departamento de Genética y Microbiología, Facultad de Biología, Universidad de Murcia, Murcia, Spain
| | - Anna Muszewska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, 02-106, Warsaw, Poland
| | | | - Gabriel Gutiérrez
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Sevilla, Spain
| | - Robert Riley
- U.S. Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Anna Lipzen
- U.S. Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Jie Guo
- U.S. Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Hope Hundley
- U.S. Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Mojgan Amirebrahimi
- U.S. Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Vivian Ng
- U.S. Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Damaris Lorenzo-Gutiérrez
- Departamento de Genética y Microbiología, Facultad de Biología, Universidad de Murcia, Murcia, Spain
| | - Ulrike Binder
- Institute of Hygiene and Medical Microbiology, Medical University of Innsbruck, Innsbruck, Austria
| | - Junhuan Yang
- College of Food Science and Engineering, Lingnan Normal University, Zhanjiang, 524048, China
| | - Yuanda Song
- Colin Ratledge Center for Microbial Lipids, School of Agricultural Engineering and Food Science, Shandong University of Technology, Zibo, 255049, China
| | - David Cánovas
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Sevilla, Spain
| | - Eusebio Navarro
- Departamento de Genética y Microbiología, Facultad de Biología, Universidad de Murcia, Murcia, Spain
| | - Michael Freitag
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR, 97331, USA
| | - Toni Gabaldón
- Barcelona Supercomputing Centre (BSC-CNS), Plaça Eusebi Güell, 1-3, 08034, Barcelona, Spain
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac, 10, 08028, Barcelona, Spain
- Catalan Institution for Research and Advanced Studies (ICREA), Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFEC), Barcelona, Spain
| | - Igor V Grigoriev
- U.S. Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Plant and Microbial Biology, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Luis M Corrochano
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Sevilla, Spain.
| | - Francisco E Nicolás
- Departamento de Genética y Microbiología, Facultad de Biología, Universidad de Murcia, Murcia, Spain.
| | - Victoriano Garre
- Departamento de Genética y Microbiología, Facultad de Biología, Universidad de Murcia, Murcia, Spain.
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Trieu TA, Duong LM, Nguyen PA, Doan TV, Nguyen HP. Myo5B plays a significant role in the hyphal growth and virulence of the human pathogenic fungus Mucor lusitanicus. MICROBIOLOGY (READING, ENGLAND) 2024; 170. [PMID: 39073411 DOI: 10.1099/mic.0.001482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/30/2024]
Abstract
Mucormycosis is an emerging and deadly invasive fungal infection caused by fungi belonging to the Mucorales order. We investigated the myosin superfamily, which encompasses diverse actin-based motor proteins with various cellular functions. Specifically, the role of the Myo5B (ID 179665) protein from the myosin class V family in Mucor lusitanicus was explored by generating silencing phenotypes and null mutants corresponding to the myo5B gene. Silencing fungal transformants exhibited a markedly reduced growth rate and a nearly complete absence of sporulation compared to the wild-type strain. The myo5BΔ null mutant strain displayed atypical characteristics, including abnormally short septa and inflated hyphae. Notably, there were a majority of small yeast-like cells instead of filamentous hyphae in the mutant. These yeast-like cells cannot germinate normally, resulting in a loss of polarity. In vivo virulence assays conducted in the Galleria mellonella invertebrate model revealed that the myo5BΔ mutant strain was avirulent. These findings shed light on the crucial contributions of the Myo5B protein to the dimorphism and pathogenicity of M. lusitanicus. Therefore, the myosin V family is a potential target for future therapeutic interventions aimed at treating mucormycosis.
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Affiliation(s)
- Trung Anh Trieu
- Faculty of Biology, Hanoi National University of Education, 136 Xuan Thuy, Cau Giay, Hanoi, Vietnam
- Present address: Navarrabiomed, Public University of Navarra, Calle de Irunlarrea, 3, 31008 Pamplona, Navarra, Spain
| | - Lam Minh Duong
- Faculty of Biology, Hanoi National University of Education, 136 Xuan Thuy, Cau Giay, Hanoi, Vietnam
| | - Phuong Anh Nguyen
- Faculty of Biology, Hanoi National University of Education, 136 Xuan Thuy, Cau Giay, Hanoi, Vietnam
| | - Thuoc Van Doan
- Faculty of Biology, Hanoi National University of Education, 136 Xuan Thuy, Cau Giay, Hanoi, Vietnam
| | - Hung Phuc Nguyen
- Faculty of Biology, Hanoi National University of Education, 136 Xuan Thuy, Cau Giay, Hanoi, Vietnam
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Panda S, Sahu MC, Turuk J, Pati S. Mucormycosis: A Rare disease to Notifiable Disease. Braz J Microbiol 2024; 55:1065-1081. [PMID: 38561499 PMCID: PMC11153412 DOI: 10.1007/s42770-024-01315-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 03/21/2024] [Indexed: 04/04/2024] Open
Abstract
Mucormycosis is the third most frequent invasive mycosis, following candidiasis and aspergillosis. It is frequently neglected due to its rare occurrence; but recently attend the status of notifiable disease due to its higher incidence in both developed and developing nations. India has received global notice since its estimated instances were greater than the global estimated figures. Mucormycosis has several clinical manifestations, including rhino-orbital-cerebral (ROCM), pulmonary, gastrointestinal, cutaneous, renal, and diffuse Mucormycosis. ROCM is the most frequent clinical manifestation in India, although pulmonary mucormycosis is prevalent worldwide. This review also discusses host defenses, pre disposing risk factors and fungal virulence factors that impair host's ability to prevent fungus invasion and disease establishment. The diagnosis of the disease depends on clinical interventions, histological or microbiological procedures along with molecular methods to obtain timely results. But there are still unmet challenges for rapid diagnosis of the disease. Treatment of the disease is achieved by multimodal approaches such as reversal of underlying predisposing factors, rapid administration of antifungals in optimal doses and surgical procedures to remove infected tissues. Liposomal Amphotericin B, Posaconazole and Isavuconazoles are preferred as the first line of treatment procedures. clinical trials. Different studies have improved the existing drug and under clinical trials while several studies predicted the new potential targets as CotH and Ftr1 as shown in infection and in vitro models. Therefore, current scenario demands a multidisciplinary approach is needed to investigate the prevalence, pathogenesis which is highly important for the advancement of rapid diagnosis and effective treatment.
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Affiliation(s)
- Sunita Panda
- Regional Medical Research Center, Bhubaneswar, Odisha, 751023, India
| | | | - Jyotirmayee Turuk
- Regional Medical Research Center, Bhubaneswar, Odisha, 751023, India.
| | - Sanghamitra Pati
- Regional Medical Research Center, Bhubaneswar, Odisha, 751023, India.
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Zhou EM, Chen XA, Zhou MM, Xu LY, Wang D, Shen HP, Xu WQ. Dissecting the genome sequence of a clinical isolated Cunninghamella bertholletiae Z2 strain with rich cytochrome P450 enzymes (Article). INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2024; 120:105575. [PMID: 38403034 DOI: 10.1016/j.meegid.2024.105575] [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: 11/06/2023] [Revised: 02/01/2024] [Accepted: 02/17/2024] [Indexed: 02/27/2024]
Abstract
Mucormycosis is receiving much more attention because of its high morbidity and extremely high mortality rate in immunosuppressed populations. In this study, we isolated a Cunnignhamella bertholletiae Z2 strain from a skin lesion of a 14 year, 9 months old girl with acute lymphoblastic leukemia who die of infection from the Z2 strain. Genome sequencing was performed after isolation and amplification of the Z2 strain to reveal potential virulence factors and pathogenic mechanisms. The results showed that the genome size of the Z2 strain is 30.9 Mb with 9213 genes. Mucoral specific virulence factor genes found are ARF, CalN, and CoTH, while no gliotoxin biosynthesis gene cluster was found, which is a known virulence factor in Aspergillus fumigatus adapted to the environment. The Z2 strain was found to have 69 cytochrome P450 enzymes, which are potential drug resistant targets. Sensitivity testing of Z2 showed it was only inhibited by amphotericin B and posaconazole. Detailed genomic information of the C. bertholletiae Z2 strain may provide useful data for treatment.
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Affiliation(s)
- En-Min Zhou
- Children's Hospital, Zhejiang University School of Medicine(ZCH), Hangzhou 310058, China
| | - Xin-Ai Chen
- Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Ming-Ming Zhou
- Children's Hospital, Zhejiang University School of Medicine(ZCH), Hangzhou 310058, China
| | - Li-Yao Xu
- Children's Hospital, Zhejiang University School of Medicine(ZCH), Hangzhou 310058, China
| | - Di Wang
- Children's Hospital, Zhejiang University School of Medicine(ZCH), Hangzhou 310058, China
| | - He-Ping Shen
- Children's Hospital, Zhejiang University School of Medicine(ZCH), Hangzhou 310058, China
| | - Wei-Qun Xu
- Children's Hospital, Zhejiang University School of Medicine(ZCH), Hangzhou 310058, China.
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8
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Navarro-Mendoza MI, Pérez-Arques C, Parker J, Xu Z, Kelly S, Heitman J. Alternative ergosterol biosynthetic pathways confer antifungal drug resistance in the human pathogens within the Mucor species complex. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.12.01.569667. [PMID: 38076934 PMCID: PMC10705545 DOI: 10.1101/2023.12.01.569667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2024]
Abstract
Mucormycoses are emerging fungal infections caused by a variety of heterogeneous species within the Mucorales order. Among the Mucor species complex, Mucor circinelloides is the most frequently isolated pathogen in mucormycosis patients and despite its clinical significance, there is an absence of established genome manipulation techniques to conduct molecular pathogenesis studies. In this study, we generated a spontaneous uracil auxotrophic strain and developed a genetic transformation procedure to analyze molecular mechanisms conferring antifungal drug resistance. With this new model, phenotypic analyses of gene deletion mutants were conducted to define Erg3 and Erg6a as key biosynthetic enzymes in the M. circinelloides ergosterol pathway. Erg3 is a C-5 sterol desaturase involved in growth, sporulation, virulence, and azole susceptibility. In other fungal pathogens, erg3 mutations confer azole resistance because Erg3 catalyzes the production of a toxic diol upon azole exposure. Surprisingly, M. circinelloides produces only trace amounts of this toxic diol and yet, it is still susceptible to posaconazole and isavuconazole due to alterations in membrane sterol composition. These alterations are severely aggravated by erg3Δ mutations, resulting in ergosterol depletion and consequently, hypersusceptibility to azoles. We also identified Erg6a as the main C-24 sterol methyltransferase, whose activity may be partially rescued by the paralogs Erg6b and Erg6c. Loss of Erg6a function diverts ergosterol synthesis to the production of cholesta-type sterols, resulting in resistance to amphotericin B. Our findings suggest that mutations or epimutations causing loss of Erg6 function may arise during human infections, resulting in antifungal drug resistance to first-line treatments against mucormycosis.
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Tanwar M, Singh A, Singh TP, Sharma S, Sharma P. Comprehensive Review on the Virulence Factors and Therapeutic Strategies with the Aid of Artificial Intelligence against Mucormycosis. ACS Infect Dis 2024; 10:1431-1457. [PMID: 38682683 DOI: 10.1021/acsinfecdis.4c00082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/01/2024]
Abstract
Mucormycosis, a rare but deadly fungal infection, was an epidemic during the COVID-19 pandemic. The rise in cases (COVID-19-associated mucormycosis, CAM) is attributed to excessive steroid and antibiotic use, poor hospital hygiene, and crowded settings. Major contributing factors include diabetes and weakened immune systems. The main manifesting forms of CAM─cutaneous, pulmonary, and the deadliest, rhinocerebral─and disseminated infections elevated mortality rates to 85%. Recent focus lies on small-molecule inhibitors due to their advantages over standard treatments like surgery and liposomal amphotericin B (which carry several long-term adverse effects), offering potential central nervous system penetration, diverse targets, and simpler dosing owing to their small size, rendering the ability to traverse the blood-brain barrier via passive diffusion facilitated by the phospholipid membrane. Adaptation and versatility in mucormycosis are facilitated by a multitude of virulence factors, enabling the pathogen to dynamically respond to various environmental stressors. A comprehensive understanding of these virulence mechanisms is imperative for devising effective therapeutic interventions against this highly opportunistic pathogen that thrives in immunocompromised individuals through its angio-invasive nature. Hence, this Review delineates the principal virulence factors of mucormycosis, the mechanisms it employs to persist in challenging host environments, and the current progress in developing small-molecule inhibitors against them.
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Affiliation(s)
- Mansi Tanwar
- Department of Biophysics, All India Institute of Medical Sciences, New Delhi-110029, India
| | - Anamika Singh
- Department of Biophysics, All India Institute of Medical Sciences, New Delhi-110029, India
| | - Tej Pal Singh
- Department of Biophysics, All India Institute of Medical Sciences, New Delhi-110029, India
| | - Sujata Sharma
- Department of Biophysics, All India Institute of Medical Sciences, New Delhi-110029, India
| | - Pradeep Sharma
- Department of Biophysics, All India Institute of Medical Sciences, New Delhi-110029, India
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10
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Lax C, Nicolás FE, Navarro E, Garre V. Molecular mechanisms that govern infection and antifungal resistance in Mucorales. Microbiol Mol Biol Rev 2024; 88:e0018822. [PMID: 38445820 PMCID: PMC10966947 DOI: 10.1128/mmbr.00188-22] [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: 03/07/2024] Open
Abstract
SUMMARYThe World Health Organization has established a fungal priority pathogens list that includes species critical or highly important to human health. Among them is the order Mucorales, a fungal group comprising at least 39 species responsible for the life-threatening infection known as mucormycosis. Despite the continuous rise in cases and the poor prognosis due to innate resistance to most antifungal drugs used in the clinic, Mucorales has received limited attention, partly because of the difficulties in performing genetic manipulations. The COVID-19 pandemic has further escalated cases, with some patients experiencing the COVID-19-associated mucormycosis, highlighting the urgent need to increase knowledge about these fungi. This review addresses significant challenges in treating the disease, including delayed and poor diagnosis, the lack of accurate global incidence estimation, and the limited treatment options. Furthermore, it focuses on the most recent discoveries regarding the mechanisms and genes involved in the development of the disease, antifungal resistance, and the host defense response. Substantial advancements have been made in identifying key fungal genes responsible for invasion and tissue damage, host receptors exploited by the fungus to invade tissues, and mechanisms of antifungal resistance. This knowledge is expected to pave the way for the development of new antifungals to combat mucormycosis. In addition, we anticipate significant progress in characterizing Mucorales biology, particularly the mechanisms involved in pathogenesis and antifungal resistance, with the possibilities offered by CRISPR-Cas9 technology for genetic manipulation of the previously intractable Mucorales species.
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Affiliation(s)
- Carlos Lax
- Departamento de Genética y Microbiología, Facultad de Biología, Universidad de Murcia, Murcia, Spain
| | - Francisco E. Nicolás
- Departamento de Genética y Microbiología, Facultad de Biología, Universidad de Murcia, Murcia, Spain
| | - Eusebio Navarro
- Departamento de Genética y Microbiología, Facultad de Biología, Universidad de Murcia, Murcia, Spain
| | - Victoriano Garre
- Departamento de Genética y Microbiología, Facultad de Biología, Universidad de Murcia, Murcia, Spain
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11
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Scheler J, Binder U. Alternative in-vivo models of mucormycosis. Front Cell Infect Microbiol 2024; 14:1343834. [PMID: 38362495 PMCID: PMC10867140 DOI: 10.3389/fcimb.2024.1343834] [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: 11/24/2023] [Accepted: 01/16/2024] [Indexed: 02/17/2024] Open
Abstract
Mucormycosis is still regarded a rare fungal infection, but the high incidences of COVID-associated cases in India and other countries have shown its potential threat to large patient cohorts. In addition, infections by these fast-growing fungi are often fatal and cause disfigurement, badly affecting patients' lives. In advancing our understanding of pathogenicity factors involved in this disease, to enhance the diagnostic toolset and to evaluate novel treatment regimes, animal models are indispensable. As ethical and practical considerations typically favor the use of alternative model systems, this review provides an overview of alternative animal models employed for mucormycosis and discusses advantages and limitations of the respective model.
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Affiliation(s)
| | - Ulrike Binder
- Department of Hygiene, Microbiology and Public Health, Division of Hygiene and Medical Microbiology, Medical University Innsbruck, Innsbruck, Tirol, Austria
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12
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Alejandre-Castañeda V, Patiño-Medina JA, Valle-Maldonado MI, García A, Ortiz-Alvarado R, Ruíz-Herrera LF, Castro-Cerritos KV, Ramírez-Emiliano J, Ramírez-Díaz MI, Garre V, Lee SC, Meza-Carmen V. Transcription Factors Tec1 and Tec2 Play Key Roles in the Hyphal Growth and Virulence of Mucor lusitanicus Through Increased Mitochondrial Oxidative Metabolism. J Microbiol 2023; 61:1043-1062. [PMID: 38114662 DOI: 10.1007/s12275-023-00096-8] [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: 08/01/2023] [Revised: 11/01/2023] [Accepted: 11/15/2023] [Indexed: 12/21/2023]
Abstract
Mucormycosis is a lethal and difficult-to-treat fungal infection caused by fungi of the order Mucorales. Mucor lusitanicus, a member of Mucorales, is commonly used as a model to understand disease pathogenesis. However, transcriptional control of hyphal growth and virulence in Mucorales is poorly understood. This study aimed to investigate the role of Tec proteins, which belong to the TEA/ATTS transcription factor family, in the hyphal development and virulence of M. lusitanicus. Unlike in the genome of Ascomycetes and Basidiomycetes, which have a single Tec homologue, in the genome of Mucorales, two Tec homologues, Tec1 and Tec2, were found, except in that of Phycomyces blakesleeanus, with only one Tec homologue. tec1 and tec2 overexpression in M. lusitanicus increased mycelial growth, mitochondrial content and activity, expression of the rhizoferrin synthetase-encoding gene rfs, and virulence in nematodes and wax moth larvae but decreased cAMP levels and protein kinase A (PKA) activity. Furthermore, tec1- and tec2-overexpressing strains required adequate mitochondrial metabolism to promote the virulent phenotype. The heterotrimeric G beta subunit 1-encoding gene deletant strain (Δgpb1) increased cAMP-PKA activity, downregulation of both tec genes, decreased both virulence and hyphal development, but tec1 and tec2 overexpression restored these defects. Overexpression of allele-mutated variants of Tec1(S332A) and Tec2(S168A) in the putative phosphorylation sites for PKA increased both virulence and hyphal growth of Δgpb1. These findings suggest that Tec homologues promote mycelial development and virulence by enhancing mitochondrial metabolism and rhizoferrin accumulation, providing new information for the rational control of the virulent phenotype of M. lusitanicus.
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Affiliation(s)
- Viridiana Alejandre-Castañeda
- Instituto de Investigaciones Químico Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Ciudad Universitaria, 58030, Morelia, Mexico
| | - J Alberto Patiño-Medina
- Instituto de Investigaciones Químico Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Ciudad Universitaria, 58030, Morelia, Mexico
| | | | - Alexis García
- Department of Molecular Microbiology and Immunology, South Texas Center for Emerging Infectious Diseases (STCEID), The University of Texas at San Antonio, San Antonio, 78249, USA
| | - Rafael Ortiz-Alvarado
- Instituto de Investigaciones Químico Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Ciudad Universitaria, 58030, Morelia, Mexico
| | - León F Ruíz-Herrera
- Instituto de Investigaciones Químico Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Ciudad Universitaria, 58030, Morelia, Mexico
| | | | | | - Martha I Ramírez-Díaz
- Instituto de Investigaciones Químico Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Ciudad Universitaria, 58030, Morelia, Mexico
| | - Victoriano Garre
- Departamento de Genética y Microbiología, Facultad de Biología, Universidad de Murcia, 30100, Murcia, Spain
| | - Soo Chan Lee
- Department of Molecular Microbiology and Immunology, South Texas Center for Emerging Infectious Diseases (STCEID), The University of Texas at San Antonio, San Antonio, 78249, USA
| | - Víctor Meza-Carmen
- Instituto de Investigaciones Químico Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Ciudad Universitaria, 58030, Morelia, Mexico.
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13
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Patiño-Medina JA, Alejandre-Castañeda V, Valle-Maldonado MI, Martínez-Pacheco MM, Ruiz-Herrera LF, Ramírez-Emiliano J, Ramírez-Marroquín OA, Castro-Cerritos KV, Campos-García J, Ramírez-Díaz MI, Garre V, Binder U, Meza-Carmen V. Blood Serum Stimulates the Virulence Potential of Mucorales through Enhancement in Mitochondrial Oxidative Metabolism and Rhizoferrin Production. J Fungi (Basel) 2023; 9:1127. [PMID: 38132728 PMCID: PMC10744254 DOI: 10.3390/jof9121127] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Revised: 11/12/2023] [Accepted: 11/20/2023] [Indexed: 12/23/2023] Open
Abstract
This study analyzed the role of blood serum in enhancing the mitochondrial metabolism and virulence of Mucorales through rhizoferrin secretion. We observed that the spores of clinically relevant Mucorales produced in the presence of serum exhibited higher virulence in a heterologous infection model of Galleria mellonella. Cell-free supernatants of the culture broth obtained from spores produced in serum showed increased toxicity against Caenorhabditis elegans, which was linked with the enhanced secretion of rhizoferrin. Spores from Mucoralean species produced or germinated in serum showed increased respiration rates and reactive oxygen species levels. The addition of non-lethal concentrations of potassium cyanide and N-acetylcysteine during the aerobic or anaerobic growth of Mucorales decreased the toxicity of the cell-free supernatants of the culture broth, suggesting that mitochondrial metabolism is important for serum-induced virulence. In support of this hypothesis, a mutant strain of Mucor lusitanicus that lacks fermentation and solely relies on oxidative metabolism exhibited virulence levels comparable to those of the wild-type strain under serum-induced conditions. Contrary to the lower virulence observed, even in the serum, the ADP-ribosylation factor-like 2 deletion strain exhibited decreased mitochondrial activity. Moreover, spores produced in the serum of M. lusitanicus and Rhizopus arrhizus that grew in the presence of a mitophagy inducer showed low virulence. These results suggest that serum-induced mitochondrial activity increases rhizoferrin levels, making Mucorales more virulent.
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Affiliation(s)
- José Alberto Patiño-Medina
- Instituto de Investigaciones Químico Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia 58030, Mexico; (J.A.P.-M.); (V.A.-C.); (M.M.M.-P.); (L.F.R.-H.); (J.C.-G.); (M.I.R.-D.)
| | - Viridiana Alejandre-Castañeda
- Instituto de Investigaciones Químico Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia 58030, Mexico; (J.A.P.-M.); (V.A.-C.); (M.M.M.-P.); (L.F.R.-H.); (J.C.-G.); (M.I.R.-D.)
| | | | - Mauro Manuel Martínez-Pacheco
- Instituto de Investigaciones Químico Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia 58030, Mexico; (J.A.P.-M.); (V.A.-C.); (M.M.M.-P.); (L.F.R.-H.); (J.C.-G.); (M.I.R.-D.)
| | - León Francisco Ruiz-Herrera
- Instituto de Investigaciones Químico Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia 58030, Mexico; (J.A.P.-M.); (V.A.-C.); (M.M.M.-P.); (L.F.R.-H.); (J.C.-G.); (M.I.R.-D.)
| | | | | | | | - Jesús Campos-García
- Instituto de Investigaciones Químico Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia 58030, Mexico; (J.A.P.-M.); (V.A.-C.); (M.M.M.-P.); (L.F.R.-H.); (J.C.-G.); (M.I.R.-D.)
| | - Martha Isela Ramírez-Díaz
- Instituto de Investigaciones Químico Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia 58030, Mexico; (J.A.P.-M.); (V.A.-C.); (M.M.M.-P.); (L.F.R.-H.); (J.C.-G.); (M.I.R.-D.)
| | - Victoriano Garre
- Departamento de Genética y Microbiología, Universidad de Murcia, 30100 Murcia, Spain;
| | - Ulrike Binder
- Institute of Hygiene and Medical Microbiology, Medical University Innsbruck, 6020 Innsbruck, Austria;
| | - Víctor Meza-Carmen
- Instituto de Investigaciones Químico Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia 58030, Mexico; (J.A.P.-M.); (V.A.-C.); (M.M.M.-P.); (L.F.R.-H.); (J.C.-G.); (M.I.R.-D.)
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14
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Alqarihi A, Kontoyiannis DP, Ibrahim AS. Mucormycosis in 2023: an update on pathogenesis and management. Front Cell Infect Microbiol 2023; 13:1254919. [PMID: 37808914 PMCID: PMC10552646 DOI: 10.3389/fcimb.2023.1254919] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 09/05/2023] [Indexed: 10/10/2023] Open
Abstract
Mucormycosis (MCR) is an emerging and frequently lethal fungal infection caused by the Mucorales family, with Rhizopus, Mucor, and Lichtheimia, accounting for > 90% of all cases. MCR is seen in patients with severe immunosuppression such as those with hematologic malignancy or transplantation, Diabetes Mellitus (DM) and diabetic ketoacidosis (DKA) and immunocompetent patients with severe wounds. The recent SARS COV2 epidemy in India has resulted in a tremendous increase in MCR cases, typically seen in the setting of uncontrolled DM and corticosteroid use. In addition to the diversity of affected hosts, MCR has pleiotropic clinical presentations, with rhino-orbital/rhino-cerebral, sino-pulmonary and necrotizing cutaneous forms being the predominant manifestations. Major insights in MCR pathogenesis have brought into focus the host receptors (GRP78) and signaling pathways (EGFR activation cascade) as well as the adhesins used by Mucorales for invasion. Furthermore, studies have expanded on the importance of iron availability and the complex regulation of iron homeostasis, as well as the pivotal role of mycotoxins as key factors for tissue invasion. The molecular toolbox to study Mucorales pathogenesis remains underdeveloped, but promise is brought by RNAi and CRISPR/Cas9 approaches. Important recent advancements have been made in early, culture-independent molecular diagnosis of MCR. However, development of new potent antifungals against Mucorales remains an unmet need. Therapy of MCR is multidisciplinary and requires a high index of suspicion for initiation of early Mucorales-active antifungals. Reversal of underlying immunosuppression, if feasible, rapid DKA correction and in selected patients, surgical debulking are crucial for improved outcomes.
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Affiliation(s)
- Abdullah Alqarihi
- Division of Infectious Diseases, The Lundquist Institute for Biomedical Innovation at Harbor-University of California Los Angeles (UCLA) Medical Center, Torrance, CA, United States
| | - Dimitrios P Kontoyiannis
- Department of Infectious Diseases, Infection Control and Employee Health, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, United States
| | - Ashraf S Ibrahim
- Division of Infectious Diseases, The Lundquist Institute for Biomedical Innovation at Harbor-University of California Los Angeles (UCLA) Medical Center, Torrance, CA, United States
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States
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15
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Puerner C, Vellanki S, Strauch JL, Cramer RA. Recent Advances in Understanding the Human Fungal Pathogen Hypoxia Response in Disease Progression. Annu Rev Microbiol 2023; 77:403-425. [PMID: 37713457 PMCID: PMC11034785 DOI: 10.1146/annurev-micro-032521-021745] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/17/2023]
Abstract
Fungal-mediated disease progression and antifungal drug efficacy are significantly impacted by the dynamic infection microenvironment. At the site of infection, oxygen often becomes limiting and induces a hypoxia response in both the fungal pathogen and host cells. The fungal hypoxia response impacts several important aspects of fungal biology that contribute to pathogenesis, virulence, antifungal drug susceptibility, and ultimately infection outcomes. In this review, we summarize recent advances in understanding the molecular mechanisms of the hypoxia response in the most common human fungal pathogens, discuss potential therapeutic opportunities, and highlight important areas for future research.
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Affiliation(s)
- Charles Puerner
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA;
| | - Sandeep Vellanki
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA;
| | - Julianne L Strauch
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA;
- Department of Biology, Dartmouth College, Hanover, New Hampshire, USA
| | - Robert A Cramer
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA;
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16
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Affiliation(s)
- Vikas Yadav
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
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17
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Bauer K, Rafael B, Vágó B, Kiss-Vetráb S, Molnár A, Szebenyi C, Varga M, Szekeres A, Vágvölgyi C, Papp T, Nagy G. Characterization of the Sterol 24-C-Methyltransferase Genes Reveals a Network of Alternative Sterol Biosynthetic Pathways in Mucor lusitanicus. Microbiol Spectr 2023; 11:e0031523. [PMID: 37036336 PMCID: PMC10269636 DOI: 10.1128/spectrum.00315-23] [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] [Received: 01/20/2023] [Accepted: 03/18/2023] [Indexed: 04/11/2023] Open
Abstract
Certain members of the order Mucorales can cause a life-threatening, often-fatal systemic infection called mucormycosis. Mucormycosis has a high mortality rate, which can reach 96 to 100% depending on the underlying condition of the patient. Mucorales species are intrinsically resistant to most antifungal agents, such as most of the azoles, which makes mucormycosis treatment challenging. The main target of azoles is the lanosterol 14α-demethylase (Erg11), which is responsible for an essential step in the biosynthesis of ergosterol, the main sterol component of the fungal membrane. Mutations in the erg11 gene can be associated with azole resistance; however, resistance can also be mediated by loss of function or mutation of other ergosterol biosynthetic enzymes, such as the sterol 24-C-methyltransferase (Erg6). The genome of Mucor lusitanicus encodes three putative erg6 genes (i.e., erg6a, erg6b, and erg6c). In this study, the role of erg6 genes in azole resistance of Mucor was analyzed by generating and analyzing knockout mutants constructed using the CRISPR-Cas9 technique. Susceptibility testing of the mutants suggested that one of the three genes, erg6b, plays a crucial role in the azole resistance of Mucor. The sterol composition of erg6b knockout mutants was significantly altered compared to that of the original strain, and it revealed the presence of at least four alternative sterol biosynthesis pathways leading to formation of ergosterol and other alternative, nontoxic sterol products. Dynamic operation of these pathways and the switching of biosynthesis from one to the other in response to azole treatment could significantly contribute to avoiding the effects of azoles by these fungi. IMPORTANCE The fungal membrane contains ergosterol instead of cholesterol, which offers a specific point of attack for the defense against pathogenic fungi. Indeed, most antifungal agents target ergosterol or its biosynthesis. Mucormycoses-causing fungi are resistant to most antifungal agents, including most of the azoles. For this reason, the drugs of choice to treat such infections are limited. The exploration of ergosterol biosynthesis is therefore of fundamental importance to understand the azole resistance of mucormycosis-causing fungi and to develop possible new control strategies. Characterization of sterol 24-C-methyltransferase demonstrated its role in the azole resistance and virulence of M. lusitanicus. Moreover, our experiments suggest that there are at least four alternative pathways for the biosynthesis of sterols in Mucor. Switching between pathways may contribute to the maintenance of azole resistance.
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Affiliation(s)
- Kitti Bauer
- Department of Microbiology, University of Szeged, Szeged, Hungary
- ELKH-SZTE Fungal Pathomechanisms Research Group, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Bence Rafael
- Department of Microbiology, University of Szeged, Szeged, Hungary
- ELKH-SZTE Fungal Pathomechanisms Research Group, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Bernadett Vágó
- Department of Microbiology, University of Szeged, Szeged, Hungary
- ELKH-SZTE Fungal Pathomechanisms Research Group, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Sándor Kiss-Vetráb
- Department of Microbiology, University of Szeged, Szeged, Hungary
- ELKH-SZTE Fungal Pathomechanisms Research Group, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Anna Molnár
- Department of Microbiology, University of Szeged, Szeged, Hungary
- ELKH-SZTE Fungal Pathomechanisms Research Group, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Csilla Szebenyi
- Department of Microbiology, University of Szeged, Szeged, Hungary
- ELKH-SZTE Fungal Pathomechanisms Research Group, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Mónika Varga
- Department of Microbiology, University of Szeged, Szeged, Hungary
| | - András Szekeres
- Department of Microbiology, University of Szeged, Szeged, Hungary
| | - Csaba Vágvölgyi
- Department of Microbiology, University of Szeged, Szeged, Hungary
- ELKH-SZTE Fungal Pathomechanisms Research Group, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Tamás Papp
- Department of Microbiology, University of Szeged, Szeged, Hungary
- ELKH-SZTE Fungal Pathomechanisms Research Group, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Gábor Nagy
- Department of Microbiology, University of Szeged, Szeged, Hungary
- ELKH-SZTE Fungal Pathomechanisms Research Group, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
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18
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Cánovas-Márquez JT, Lax C, Tahiri G, Navarro E, Nicolás FE, Garre V. Advances in understanding infections caused by the basal fungus Mucor. PLoS Pathog 2023; 19:e1011394. [PMID: 37262085 DOI: 10.1371/journal.ppat.1011394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023] Open
Affiliation(s)
- José T Cánovas-Márquez
- Departamento de Genética y Microbiología, Facultad de Biología, Universidad de Murcia, Murcia, Spain
| | - Carlos Lax
- Departamento de Genética y Microbiología, Facultad de Biología, Universidad de Murcia, Murcia, Spain
| | - Ghizlane Tahiri
- Departamento de Genética y Microbiología, Facultad de Biología, Universidad de Murcia, Murcia, Spain
| | - Eusebio Navarro
- Departamento de Genética y Microbiología, Facultad de Biología, Universidad de Murcia, Murcia, Spain
| | - Francisco E Nicolás
- Departamento de Genética y Microbiología, Facultad de Biología, Universidad de Murcia, Murcia, Spain
| | - Victoriano Garre
- Departamento de Genética y Microbiología, Facultad de Biología, Universidad de Murcia, Murcia, Spain
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19
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Mucorales and Mucormycosis: Recent Insights and Future Prospects. J Fungi (Basel) 2023; 9:jof9030335. [PMID: 36983503 PMCID: PMC10058716 DOI: 10.3390/jof9030335] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 02/28/2023] [Accepted: 03/04/2023] [Indexed: 03/11/2023] Open
Abstract
The classification of Mucorales encompasses a collection of basal fungi that have traditionally demonstrated an aversion to modern genetic manipulation techniques. This aversion led to a scarcity of knowledge regarding their biology compared to other fungal groups. However, the emergence of mucormycosis, a fungal disease caused by Mucorales, has attracted the attention of the clinical field, mainly because available therapies are ineffective for decreasing the fatal outcome associated with the disease. This revitalized curiosity about Mucorales and mucormycosis, also encouraged by the recent COVID-19 pandemic, has spurred a significant and productive effort to uncover their mysteries in recent years. Here, we elaborate on the most remarkable breakthroughs related to the recently discovered genetic advances in Mucorales and mucormycosis. The utilization of a few genetic study models has enabled the identification of virulence factors in Mucorales that were previously described in other pathogens. More notably, recent investigations have identified novel genes and mechanisms controlling the pathogenic potential of Mucorales and their interactions with the host, providing fresh avenues to devise new strategies against mucormycosis. Finally, new study models are allowing virulence studies that were previously hampered in Mucorales, predicting a prolific future for the field.
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Szebenyi C, Gu Y, Gebremariam T, Kocsubé S, Kiss-Vetráb S, Jáger O, Patai R, Spisák K, Sinka R, Binder U, Homa M, Vágvölgyi C, Ibrahim AS, Nagy G, Papp T. cotH Genes Are Necessary for Normal Spore Formation and Virulence in Mucor lusitanicus. mBio 2023; 14:e0338622. [PMID: 36625576 PMCID: PMC9973265 DOI: 10.1128/mbio.03386-22] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Accepted: 12/14/2022] [Indexed: 01/11/2023] Open
Abstract
Mucormycosis is an invasive fungal infection caused by certain members of the fungal order of Mucorales. The species most frequently identified as the etiological agents of mucormycosis belong to the genera Rhizopus, Lichtheimia, and Mucor. The frequency of systemic mucormycosis has been increasing, mainly because of increasing numbers of susceptible patients. Furthermore, Mucorales display intrinsic resistance to the majority of routinely used antifungal agents (e.g., echinocandins and short-tailed azoles), which limits the number of possible therapeutic options. All the above-mentioned issues urge the improvement of molecular identification methods and the discovery of new antifungal targets and strategies. Spore coat proteins (CotH) constitute a kinase family present in many pathogenic bacteria and fungi and participate in the spore formation in these organisms. Moreover, some of them can act as virulence factors being receptors of the human GRP78 protein during Rhizopus delemar-induced mucormycosis. We identified 17 cotH-like genes in the Mucor lusitanicus genome database. Successful disruption of five cotH genes in Mucor was performed using the CRISPR-Cas9 system. The CotH3 and CotH4 proteins play a role in adaptation to different temperatures as well as in developing the cell wall structure. We also show CotH4 protein is involved in spore wall formation by affecting the total chitin content and, thus, the composition of the spore wall. The role of CotH3 and CotH4 proteins in virulence was confirmed in two invertebrate models and a diabetic ketoacidosis (DKA) mouse model. IMPORTANCE Current treatment options for mucormycosis are inadequate, resulting in high mortality rates, especially among immunosuppressed patients. The development of novel therapies for mucormycosis has been hampered by lack of understanding of the pathogenetic mechanisms. The importance of the cell surface CotH proteins in the pathogenesis of Rhizopus-mediated mucormycosis has been recently described. However, the contribution of this family of proteins to the virulence of other mucoralean fungi and their functionality in vital processes remain undefined. Through the use of the CRISPR-Case9 gene disruption system, we demonstrate the importance of several of the CotH proteins to the virulence of Mucor lusitanicus by using three infection models. We also report on the importance of one of these proteins, CotH4, to spore wall formation by affecting chitin content. Therefore, our studies extend the importance of CotH proteins to Mucor and identify the mechanism by which one of the CotH proteins contributes to the development of a normal fungal cell wall, thereby indicating that this family of proteins can be targeted for future development of novel therapeutic strategies of mucormycosis.
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Affiliation(s)
- Csilla Szebenyi
- Department of Microbiology, University of Szeged, Szeged, Hungary
- ELKH-SZTE Fungal Pathomechanisms Research Group, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Yiyou Gu
- Division of Infectious Diseases, The Lundquist Institute for Biomedical Innovation at Harbor-University of California Los Angeles (UCLA) Medical Center, Torrance, California, USA
| | - Teclegiorgis Gebremariam
- Division of Infectious Diseases, The Lundquist Institute for Biomedical Innovation at Harbor-University of California Los Angeles (UCLA) Medical Center, Torrance, California, USA
| | - Sándor Kocsubé
- Department of Microbiology, University of Szeged, Szeged, Hungary
- ELKH-SZTE Fungal Pathomechanisms Research Group, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Sándor Kiss-Vetráb
- Department of Microbiology, University of Szeged, Szeged, Hungary
- ELKH-SZTE Fungal Pathomechanisms Research Group, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Olivér Jáger
- Department of Microbiology, University of Szeged, Szeged, Hungary
- ELKH-SZTE Fungal Pathomechanisms Research Group, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Roland Patai
- Institute of Biophysics, Biological Research Centre, Szeged, Hungary
| | - Krisztina Spisák
- Institute of Biophysics, Biological Research Centre, Szeged, Hungary
- Doctoral School of Theoretical Medicine, University of Szeged, Szeged, Hungary
| | - Rita Sinka
- Department of Genetics, University of Szeged, Szeged, Hungary
| | - Ulrike Binder
- Institute of Hygiene and Medical Microbiology, Medical University of Innsbruck, Innsbruck, Austria
| | - Mónika Homa
- Department of Microbiology, University of Szeged, Szeged, Hungary
- ELKH-SZTE Fungal Pathomechanisms Research Group, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Csaba Vágvölgyi
- Department of Microbiology, University of Szeged, Szeged, Hungary
- ELKH-SZTE Fungal Pathomechanisms Research Group, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Ashraf S. Ibrahim
- Division of Infectious Diseases, The Lundquist Institute for Biomedical Innovation at Harbor-University of California Los Angeles (UCLA) Medical Center, Torrance, California, USA
- David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Gábor Nagy
- Department of Microbiology, University of Szeged, Szeged, Hungary
- ELKH-SZTE Fungal Pathomechanisms Research Group, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Tamás Papp
- Department of Microbiology, University of Szeged, Szeged, Hungary
- ELKH-SZTE Fungal Pathomechanisms Research Group, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
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Serine/Threonine Phosphatase Calcineurin Orchestrates the Intrinsic Resistance to Micafungin in the Human-Pathogenic Fungus Mucor circinelloides. Antimicrob Agents Chemother 2023; 67:e0068622. [PMID: 36688672 PMCID: PMC9933632 DOI: 10.1128/aac.00686-22] [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] [Indexed: 01/24/2023] Open
Abstract
Procedures such as solid-organ transplants and cancer treatments can leave many patients in an immunocompromised state. This leads to their increased susceptibility to opportunistic diseases such as fungal infections. Mucormycosis infections are continually emerging and pose a serious threat to immunocompromised patients. Recently there has been a sharp increase in mucormycosis cases as a secondary infection in patients battling severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections. Mucorales fungi are notorious for presenting resistance to most antifungal drugs. The absence of effective means to treat these infections results in mortality rates approaching 100% in cases of disseminated infection. One of the most effective antifungal drug classes currently available is the echinocandins. Echinocandins seem to be efficacious in the treatment of many other fungal infections. Unfortunately, susceptibility testing has found that echinocandins have little to no effect on Mucorales fungi. In this study, we found that the model Mucorales Mucor circinelloides genome carries three copies of the genes encoding the echinocandin target protein β-(1,3)-d-glucan synthase (fksA, fksB, and fksC). Interestingly, we found that exposing M. circinelloides to micafungin significantly increased the expression of the fksA and fksB genes, resulting in an increased accumulation of β-(1,3)-d-glucan on the cell walls. However, this overexpression of the fks genes is not directly connected to the intrinsic resistance. Subsequent investigation discovered that the serine/threonine phosphatase calcineurin regulates the expression of fksA and fksB, and the deletion of calcineurin results in a decrease in expression of all three fks genes. Deletion of calcineurin also results in a lower minimum effective concentration (MEC) of micafungin. In addition, we found that duplication of the fks gene is also responsible for the intrinsic resistance, in which lack of either fksA or fksB led a lower MEC of micafungin. Together, these findings demonstrate that calcineurin and fks gene duplication contribute to the intrinsic resistance to micafungin we observe in M. circinelloides.
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Nimoshini G, Nataraj P, Rameshkumar A, Krishnan R, Savithri S. Inhibitory effect of garlic and omam extracts on Mucor circinelloides, a fungus causing mucormycosis: An in vitro study. J Oral Maxillofac Pathol 2023; 27:71-75. [PMID: 37234326 PMCID: PMC10207184 DOI: 10.4103/jomfp.jomfp_45_22] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 03/22/2022] [Indexed: 05/27/2023] Open
Abstract
Context Mucor circinelloides is reported to be the second among the most common causative agents of emerging mucormycosis. It is intrinsically resistant to most known antifungals. Further the use of antifungals cause side effects. Traditional knowledge system for treating various ailments is stronger in India and it also backs deriving various bioactive compounds from herbal sources, in the modern system of medicine. Therefore, two most commonly used culinary herbal materials viz., ginger and omam were studied in vitro against M. circinelloides, as an alternate to antifungal drugs. Aims To explore the traditional herbal resources as alternate to Amphotericin B to use against M. circinelloides, a fungus causing mucormycosis. Methods and Material Aqueous extracts of garlic and omam were prepared and tested against M. circinelloides, at different concentrations. A positive control with Amphotericin B and negative control without any supplements were also maintained. The inhibitory effect was assessed by adopting optical density (OD) measurement method in SD broth and SD Agar Well Plate using spore suspension as inoculum. Statistical Analysis Used Paired student T test was employed using SPSS Version 1.6. Results and Conclusions Both garlic and omam extracts were found to inhibit the M. circinelloides and their MICs were 600 and 700 μL/mL. It is comparable with the MIC of Amphotericin B, 200 μg/mL. Thus, the regular use of garlic and omam can reduce the risk of possible mucormycosis and these herbs can be explored for drug formulations against M. circinelloides.
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Affiliation(s)
- G Nimoshini
- Department of Oral Pathology and Microbiology, SRM Dental College, Ramapuram, Chennai, Tamil Nadu, India
| | - Priyadharsini Nataraj
- Department of Oral Pathology and Microbiology, SRM Dental College, Ramapuram, Chennai, Tamil Nadu, India
| | - Annasamy Rameshkumar
- Department of Oral Pathology and Microbiology, SRM Dental College, Ramapuram, Chennai, Tamil Nadu, India
| | - Rajkumar Krishnan
- Department of Oral Pathology and Microbiology, SRM Dental College, Ramapuram, Chennai, Tamil Nadu, India
| | - S. Savithri
- Microbiology, SRM Dental College, Ramapuram, Chennai, Tamil Nadu, India
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Trieu TA, Nguyen PA, Le MN, Chu HN. Myosin-II proteins are involved in the growth, morphogenesis, and virulence of the human pathogenic fungus Mucor circinelloides. Front Cell Infect Microbiol 2022; 12:1031463. [PMID: 36590583 PMCID: PMC9800795 DOI: 10.3389/fcimb.2022.1031463] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 11/25/2022] [Indexed: 12/23/2022] Open
Abstract
Mucormycosis is an emerging lethal invasive fungal infection. The infection caused by fungi belonging to the order Mucorales has been reported recently as one of the most common fungal infections among COVID-19 patients. The lack of understanding of pathogens, particularly at the molecular level, is one of the reasons for the difficulties in the management of the infection. Myosin is a diverse superfamily of actin-based motor proteins that have various cellular roles. Four families of myosin motors have been found in filamentous fungi, including myosin I, II, V, and fungus-specific chitin synthase with myosin motor domains. Our previous study on Mucor circinelloides, a common pathogen of mucormycosis, showed that the Myo5 protein (ID 51513) belonging to the myosin type V family had a critical impact on the growth and virulence of this fungus. In this study, to investigate the roles of myosin II proteins in M. circinelloides, silencing phenotypes and null mutants corresponding to myosin II encoding genes, designated mcmyo2A (ID 149958) and mcmyo2B (ID 136314), respectively, were generated. Those mutant strains featured a significantly reduced growth rate and impaired sporulation in comparison with the wild-type strain. Notably, the disruption of mcmyo2A led to an almost complete lack of sporulation. Both mutant strains displayed abnormally short, septate, and inflated hyphae with the presence of yeast-like cells and an unusual accumulation of pigment-filled vesicles. In vivo virulence assays of myosin-II mutant strains performed in the invertebrate model Galleria mellonella indicated that the mcmyo2A-knockout strain was avirulent, while the pathogenesis of the mcmyo2B null mutant was unaltered despite the low growth rate and impaired sporulation. The findings provide suggestions for critical contributions of the myosin II proteins to the polarity growth, septation, morphology, pigment transportation, and pathogenesis of M. circinelloides. The findings also implicate the myosin family as a potential target for future therapy to treat mucormycosis.
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Affiliation(s)
- Trung Anh Trieu
- Department of Genetics - Biochemistry, Faculty of Biology, Hanoi National University of Education, Hanoi, Vietnam,*Correspondence: Trung Anh Trieu,
| | - Phuong Anh Nguyen
- Department of Genetics - Biochemistry, Faculty of Biology, Hanoi National University of Education, Hanoi, Vietnam
| | - Mai Ngoc Le
- Department of Genetics - Biochemistry, Faculty of Biology, Hanoi National University of Education, Hanoi, Vietnam
| | - Huy Nhat Chu
- Environmental Bioremediation Laboratory, Institute of Biotechnology, Vietnam Academy of Science and Technology, Hanoi, Vietnam,Graduate University of Science and Technology, Vietnam Academy of Science and Technology, Hanoi, Vietnam
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Acosta-España JD, Voigt K. An old confusion: Entomophthoromycosis versus mucormycosis and their main differences. Front Microbiol 2022; 13:1035100. [PMID: 36406416 PMCID: PMC9670544 DOI: 10.3389/fmicb.2022.1035100] [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: 09/02/2022] [Accepted: 09/29/2022] [Indexed: 11/06/2022] Open
Abstract
Fungal diseases were underestimated for many years. And the global burden of fungal infections is substantial and has increased in recent years. Invasive fungal infections have been linked to several risk factors in humans which basically depend on the individual homeostasis of the patients. However, many fungi can infect even apparently healthy people. Knowledge of these pathogens is critical in reducing or stopping morbidity and/or mortality statistics due to fungal pathogens. Successful therapeutic strategies rely on rapid diagnosis of the causative fungal agent and the underlying disease. However, the terminology of the diseases was updated to existing phylogenetic classifications and led to confusion in the definition of mucormycosis, conidiobolomycosis, and basidiobolomycosis, which were previously grouped under the now-uncommon term zygomycosis. Therefore, the ecological, taxonomic, clinical, and diagnostic differences are addressed to optimize the understanding and definition of these diseases. The term "coenocytic hyphomycosis" is proposed to summarize all fungal infections caused by Mucorales and species of Basidiobolus and Conidiobolus.
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Affiliation(s)
- Jaime David Acosta-España
- Jena Microbial Resource Collection, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knöll Institute, Jena, Germany,Institute of Microbiology, Friedrich Schiller University Jena, Jena, Germany,Postgraduate Program in Infectious Diseases, School of Medicine, Pontificia Universidad Católica del Ecuador, Quito, Ecuador
| | - Kerstin Voigt
- Jena Microbial Resource Collection, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knöll Institute, Jena, Germany,Institute of Microbiology, Friedrich Schiller University Jena, Jena, Germany,*Correspondence: Kerstin Voigt,
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25
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Key molecules of Mucorales for COVID-19-associated mucormycosis: a narrative review. JOURNAL OF BIO-X RESEARCH 2022. [DOI: 10.1097/jbr.0000000000000131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Abstract
Coronavirus disease 2019 (COVID-19)-associated invasive fungal infections are an important complication in a substantial number of critically ill, hospitalized patients with COVID-19. Three groups of fungal pathogens cause co-infections in COVID-19: Aspergillus, Mucorales and Candida species, including Candida auris. Here we review the incidence of COVID-19-associated invasive fungal infections caused by these fungi in low-, middle- and high-income countries. By evaluating the epidemiology, clinical risk factors, predisposing features of the host environment and immunological mechanisms that underlie the pathogenesis of these co-infections, we set the scene for future research and development of clinical guidance. Hoenigl and colleagues review the epidemiology, immunology and clinical risk factors contributing to COVID-19-associated fungal infections.
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Secretion of the siderophore rhizoferrin is regulated by the cAMP-PKA pathway and is involved in the virulence of Mucor lusitanicus. Sci Rep 2022; 12:10649. [PMID: 35739200 PMCID: PMC9226013 DOI: 10.1038/s41598-022-14515-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 06/08/2022] [Indexed: 11/08/2022] Open
Abstract
Mucormycosis is a fungal infection caused by Mucorales, with a high mortality rate. However, only a few virulence factors have been described in these organisms. This study showed that deletion of rfs, which encodes the enzyme for the biosynthesis of rhizoferrin, a siderophore, in Mucor lusitanicus, led to a lower virulence in diabetic mice and nematodes. Upregulation of rfs correlated with the increased toxicity of the cell-free supernatants of the culture broth (SS) obtained under growing conditions that favor oxidative metabolism, such as low glucose levels or the presence of H2O2 in the culture, suggesting that oxidative metabolism enhances virulence through rhizoferrin production. Meanwhile, growing M. lusitanicus in the presence of potassium cyanide, N-acetylcysteine, a higher concentration of glucose, or exogenous cAMP, or the deletion of the gene encoding the regulatory subunit of PKA (pkaR1), correlated with a decrease in the toxicity of SS, downregulation of rfs, and reduction in rhizoferrin production. These observations indicate the involvement of the cAMP-PKA pathway in the regulation of rhizoferrin production and virulence in M. lusitanicus. Moreover, rfs upregulation was observed upon macrophage interaction or during infection with spores in mice, suggesting a pivotal role of rfs in M. lusitanicus infection.
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The Entomopathogenic Fungus Beauveria bassiana Shows Its Toxic Side within Insects: Expression of Genes Encoding Secondary Metabolites during Pathogenesis. J Fungi (Basel) 2022; 8:jof8050488. [PMID: 35628744 PMCID: PMC9143124 DOI: 10.3390/jof8050488] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 05/05/2022] [Accepted: 05/06/2022] [Indexed: 01/23/2023] Open
Abstract
Entomopathogenic fungi are extensively used for the control of insect pests worldwide. Among them, Beauveria bassiana (Ascomycota: Hypocreales) produce a plethora of toxic secondary metabolites that either facilitate fungal invasion or act as immunosuppressive compounds. These toxins have different chemical natures, such as nonribosomal peptides and polyketides. Even though their precise role is poorly understood, they are usually linked to virulence. These fungal secondary metabolites are produced by the expression of gene clusters encoding the various proteins needed for their biosynthesis. Each cluster includes synthetases for nonribosomal peptides (NRPS), polyketides (PKS), or hybrid NRPS–PKS genes. The aim of this review is to summarize the information available from transcriptomics and quantitative PCR studies related to the expression of B. bassiana NRPS and PKS genes inside different insects as the infection progresses; as for the host immune response, to help understand the mechanisms that these toxins trigger as virulence factors, antimicrobials, or immunosuppressives within the context of a fungus–insect interaction.
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29
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Homa M, Ibragimova S, Szebenyi C, Nagy G, Zsindely N, Bodai L, Vágvölgyi C, Nagy G, Papp T. Differential Gene Expression of Mucor lusitanicus under Aerobic and Anaerobic Conditions. J Fungi (Basel) 2022; 8:jof8040404. [PMID: 35448635 PMCID: PMC9031258 DOI: 10.3390/jof8040404] [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: 02/21/2022] [Revised: 04/12/2022] [Accepted: 04/14/2022] [Indexed: 02/04/2023] Open
Abstract
Mucor lusitanicus and some other members of the fungal order Mucorales display the phenomenon of morphological dimorphism. This means that these fungi aerobically produce filamentous hyphae, developing a coenocytic mycelium, but they grow in a multipolar yeast-like form under anaerobiosis. Revealing the molecular mechanism of the reversible yeast-hyphal transition can be interesting for both the biotechnological application and in the understanding of the pathomechanism of mucormycosis. In the present study, transcriptomic analyses were carried out after cultivating the fungus either aerobically or anaerobically revealing significant changes in gene expression under the two conditions. In total, 539 differentially expressed genes (FDR < 0.05, |log2FC| ≥ 3) were identified, including 190 upregulated and 349 downregulated transcripts. Within the metabolism-related genes, carbohydrate metabolism was proven to be especially affected. Anaerobiosis also affected the transcription of transporters: among the 14 up- and 42 downregulated transporters, several putative sugar transporters were detected. Moreover, a considerable number of transcripts related to amino acid transport and metabolism, lipid transport and metabolism, and energy production and conversion were proven to be downregulated when the culture had been transferred into an anaerobic atmosphere.
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Affiliation(s)
- Mónika Homa
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, H-6726 Szeged, Hungary; (M.H.); (S.I.); (C.S.); (C.V.); (G.N.)
| | - Sandugash Ibragimova
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, H-6726 Szeged, Hungary; (M.H.); (S.I.); (C.S.); (C.V.); (G.N.)
| | - Csilla Szebenyi
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, H-6726 Szeged, Hungary; (M.H.); (S.I.); (C.S.); (C.V.); (G.N.)
| | - Gábor Nagy
- Department of Biochemistry and Molecular Biology, Faculty of Science and Informatics, University of Szeged, H-6726 Szeged, Hungary; (G.N.); (L.B.)
| | - Nóra Zsindely
- Department of Genetics, Faculty of Science and Informatics, University of Szeged, H-6726 Szeged, Hungary;
| | - László Bodai
- Department of Biochemistry and Molecular Biology, Faculty of Science and Informatics, University of Szeged, H-6726 Szeged, Hungary; (G.N.); (L.B.)
| | - Csaba Vágvölgyi
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, H-6726 Szeged, Hungary; (M.H.); (S.I.); (C.S.); (C.V.); (G.N.)
| | - Gábor Nagy
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, H-6726 Szeged, Hungary; (M.H.); (S.I.); (C.S.); (C.V.); (G.N.)
| | - Tamás Papp
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, H-6726 Szeged, Hungary; (M.H.); (S.I.); (C.S.); (C.V.); (G.N.)
- Correspondence:
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Genetic Manipulation in Mucorales and New Developments to Study Mucormycosis. Int J Mol Sci 2022; 23:ijms23073454. [PMID: 35408814 PMCID: PMC8998210 DOI: 10.3390/ijms23073454] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 03/16/2022] [Accepted: 03/18/2022] [Indexed: 12/04/2022] Open
Abstract
The study of the Mucoralean fungi physiology is a neglected field that the lack of effective genetic tools has hampered in the past. However, the emerging fungal infection caused by these fungi, known as mucormycosis, has prompted many researchers to study the pathogenic potential of Mucorales. The main reasons for this current attraction to study mucormycosis are its high lethality, the lack of effective antifungal drugs, and its recent increased incidence. The most contemporary example of the emergence character of mucormycosis is the epidemics declared in several Asian countries as a direct consequence of the COVID-19 pandemic. Fortunately, this pressure to understand mucormycosis and develop new treatment strategies has encouraged the blossoming of new genetic techniques and methodologies. This review describes the history of genetic manipulation in Mucorales, highlighting the development of methods and how they allowed the main genetic studies in these fungi. Moreover, we have emphasized the recent development of new genetic models to study mucormycosis, a landmark in the field that will configure future research related to this disease.
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Recent Molecular Tools for the Genetic Manipulation of Highly Industrially Important Mucoromycota Fungi. J Fungi (Basel) 2021; 7:jof7121061. [PMID: 34947043 PMCID: PMC8705501 DOI: 10.3390/jof7121061] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 11/27/2021] [Accepted: 12/06/2021] [Indexed: 12/20/2022] Open
Abstract
Mucorales is the largest and most well-studied order of the phylum Mucormycota and is known for its rapid growth rate and various industrial applications. The Mucorales fungi are a fascinating group of filamentous organisms with many uses in research and the industrial and medical fields. They are widely used biotechnological producers of various secondary metabolites and other value-added products. Certain members of Mucorales are extensively used as model organisms for genetic and molecular investigation and have extended our understanding of the metabolisms of other members of this order as well. Compared with other fungal species, our understanding of Mucoralean fungi is still in its infancy, which could be linked to their lack of effective genetic tools. However, recent advancements in molecular tools and approaches, such as the construction of recyclable markers, silencing vectors, and the CRISPR-Cas9-based gene-editing system, have helped us to modify the genomes of these model organisms. Multiple genetic modifications have been shown to generate valuable products on a large scale and helped us to understand the morphogenesis, basic biology, pathogenesis, and host–pathogen interactions of Mucoralean fungi. In this review, we discuss various conventional and modern genetic tools and approaches used for efficient gene modification in industrially important members of Mucorales.
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Sen A. Deficient synthesis of melatonin in COVID-19 can impair the resistance of coronavirus patients to mucormycosis. Med Hypotheses 2021; 158:110722. [PMID: 34753008 PMCID: PMC8553412 DOI: 10.1016/j.mehy.2021.110722] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 10/12/2021] [Accepted: 10/17/2021] [Indexed: 12/25/2022]
Abstract
In addition to uncontrolled diabetes and the excess use of corticosteroids, it is believed that other factors may be responsible for the recent spurt of COVID-19 associated mucormycosis (CAM). In the present paper it is argued that COVID-19 increases the susceptibility of the patients to mucormycosis by augmenting the virulence factors of the mucor species, where deficient synthesis of melatonin plays a key role. Melatonin is synthesized from tryptophan via the serotonin pathway and melatonin deficiency in COVID-19 arises from the faulty absorption of tryptophan from the food because SARS-CoV-2 downregulates angiotensin-converting enzyme-2, the chaperone of the transporter of tryptophan. The enhanced fungal virulence in COVID-19 can be mitigated by correcting the melatonin deficiency as melatonin can prevent iron acquisition of the mucor species and inhibit their morphological transition from the yeast to the virulent hyphal form, given the fact that melatonin is an iron chelator, calmodulin blocker and inhibitor of myeloperoxidase as well as inhibitor of ferroptosis and pyroptosis. Also, by lowering the expression of glucose-regulated protein 78 and by inhibiting the suppression of T-cell immunity, melatonin can further increase the resistance of the patients to mucormycosis. Accordingly, clinical trials should be carried out on tryptophan supplementation, administration of selective serotonin reuptake inhibitors (to increase serotonin, the precursor of melatonin), and exogenous melatonin to find out how they perform in eliminating or reducing the propensity of the coronavirus patients to CAM.
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Affiliation(s)
- Amarnath Sen
- 40 Jadunath Sarbovouma Lane, Kolkata 700035, India.
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DNA Methylation on N6-Adenine Regulates the Hyphal Development during Dimorphism in the Early-Diverging Fungus Mucor lusitanicus. J Fungi (Basel) 2021; 7:jof7090738. [PMID: 34575776 PMCID: PMC8470550 DOI: 10.3390/jof7090738] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 09/03/2021] [Accepted: 09/06/2021] [Indexed: 12/14/2022] Open
Abstract
The epigenetic modifications control the pathogenicity of human pathogenic fungi, which have been poorly studied in Mucorales, causative agents of mucormycosis. This order belongs to a group referred to as early-diverging fungi that are characterized by high levels of N6-methyldeoxy adenine (6mA) in their genome with dense 6mA clusters associated with actively expressed genes. AlkB enzymes can act as demethylases of 6mA in DNA, with the most remarkable eukaryotic examples being mammalian ALKBH1 and Caenorhabditis elegans NMAD-1. The Mucor lusitanicus (formerly M. circinelloides f. lusitanicus) genome contains one gene, dmt1, and two genes, dmt2 and dmt3, encoding proteins similar to C. elegans NMAD-1 and ALKBH1, respectively. The function of these three genes was analyzed by the generation of single and double deletion mutants for each gene. Multiple processes were studied in the mutants, but defects were only found in single and double deletion mutants for dmt1. In contrast to the wild-type strain, dmt1 mutants showed an increase in 6mA levels during the dimorphic transition, suggesting that 6mA is associated with dimorphism in M. lusitanicus. Furthermore, the spores of dmt1 mutants challenged with macrophages underwent a reduction in polar growth, suggesting that 6mA also has a role during the spore–macrophage interaction that could be important in the infection process.
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Prakash H, Skiada A, Paul RA, Chakrabarti A, Rudramurthy SM. Connecting the Dots: Interplay of Pathogenic Mechanisms between COVID-19 Disease and Mucormycosis. J Fungi (Basel) 2021; 7:616. [PMID: 34436155 PMCID: PMC8400165 DOI: 10.3390/jof7080616] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 07/20/2021] [Accepted: 07/26/2021] [Indexed: 01/08/2023] Open
Abstract
Coronavirus disease (COVID-19)-associated mucormycosis (CAM) is an emerging threat globally, especially in India. More than 40,000 CAM cases have been reported in India. The emergence of CAM cases in India has been attributed to environmental, host, and iatrogenic factors. Mucorales spore burden has been reported globally; however, their presence is higher in tropical countries such as India, contributing to the emergence of CAM. Before the COVID-19 pandemic, patients with diabetes mellitus, haematological malignancies, solid organ transplants, corticosteroid therapy and neutropenia were more prone to mucormycosis, whereas in COVID-19 patients, virus-induced endothelial dysfunction, hyperglycaemia, and immune dysfunction following corticosteroid use increase the risk of acquiring mucormycosis. The interaction of Mucorales spores with the epithelial cells, followed by endothelial invasion, is a crucial step in the pathogenesis of mucormycosis. Endothelial damage and increased endothelial receptor expression induced by COVID-19 infection may predispose patients to CAM. COVID-19 infection may directly induce hyperglycaemia by damaging beta cells of the pancreas or by corticosteroid therapy, which may contribute to CAM pathogenesis. Iron acquisition from the host, especially in diabetic ketoacidosis (DKA) or deferoxamine therapy, is an important virulence trait of Mucorales. Similarly, the hyperferritinaemia caused by COVID-19 may act as a source of iron for Mucorales growth and invasion. In addition, corticosteroid treatment reduces or abolishes the innate immune functions of phagocytic cells contributing to the pathogenesis of CAM. This review aims to discuss primarily the host and iatrogenic factors shared between COVID-19 and mucormycosis that could explain the emergence of CAM.
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Affiliation(s)
- Hariprasath Prakash
- Medical Microbiology, Department of Public Health, International Higher School of Medicine, Issyk-Kul Regional Campus, Cholpon-Ata 722125, Kyrgyzstan;
| | - Anna Skiada
- First Department of Medicine, Laiko Hospital, National and Kapodistrian University of Athens, 11527 Athens, Greece;
| | - Raees Ahmad Paul
- Department of Medical Microbiology, Postgraduate Institute of Medical Education and Research, Chandigarh 160012, India; (R.A.P.); (A.C.)
| | - Arunaloke Chakrabarti
- Department of Medical Microbiology, Postgraduate Institute of Medical Education and Research, Chandigarh 160012, India; (R.A.P.); (A.C.)
| | - Shivaprakash Mandya Rudramurthy
- Department of Medical Microbiology, Postgraduate Institute of Medical Education and Research, Chandigarh 160012, India; (R.A.P.); (A.C.)
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35
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Arana C, Cuevas Ramírez RE, Xipell M, Casals J, Moreno A, Herrera S, Bodro M, Cofan F, Diekmann F, Esforzado N. Mucormycosis associated with COVID-19 in two kidney transplant patients. Transpl Infect Dis 2021; 23:e13652. [PMID: 34038014 PMCID: PMC8209809 DOI: 10.1111/tid.13652] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 05/12/2021] [Accepted: 05/18/2021] [Indexed: 12/14/2022]
Abstract
Coronavirus disease 2019 (COVID‐19) predisposes patients to bacterial and fungal superinfections due to the impairment of the immunological system. Among the associated opportunistic fungal infections, mucormycosis is one of the least frequent but with the highest mortality. We describe two cases of mucormycosis in two kidney transplant recipients, while they were hospitalized for SARS‐CoV‐2 pneumonia, with rhinosinusal and musculoskeletal involvement, respectively.
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Affiliation(s)
- Carolt Arana
- Department of Nephrology, Fundació Puigvert, Barcelona, Spain
| | - Rafael E Cuevas Ramírez
- Department of Nephrology and Renal Transplantation, Hospital Clinic de Barcelona, Barcelona, Spain
| | - Marc Xipell
- Department of Nephrology and Renal Transplantation, Hospital Clinic de Barcelona, Barcelona, Spain
| | - Joaquim Casals
- Department of Nephrology and Renal Transplantation, Hospital Clinic de Barcelona, Barcelona, Spain
| | - Asunción Moreno
- Department of Infectious Diseases, Hospital Clinic Barcelona, Barcelona, Spain
| | - Sabina Herrera
- Department of Infectious Diseases, Hospital Clinic Barcelona, Barcelona, Spain
| | - Marta Bodro
- Department of Infectious Diseases, Hospital Clinic Barcelona, Barcelona, Spain
| | - Frederic Cofan
- Department of Nephrology and Renal Transplantation, Hospital Clinic de Barcelona, Barcelona, Spain
| | - Fritz Diekmann
- Department of Nephrology and Renal Transplantation, Hospital Clinic de Barcelona, Barcelona, Spain
| | - Núria Esforzado
- Department of Nephrology and Renal Transplantation, Hospital Clinic de Barcelona, Barcelona, Spain
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36
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Chiou JG, Moran KD, Lew DJ. How cells determine the number of polarity sites. eLife 2021; 10:e58768. [PMID: 33899733 PMCID: PMC8116050 DOI: 10.7554/elife.58768] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Accepted: 04/23/2021] [Indexed: 12/15/2022] Open
Abstract
The diversity of cell morphologies arises, in part, through regulation of cell polarity by Rho-family GTPases. A poorly understood but fundamental question concerns the regulatory mechanisms by which different cells generate different numbers of polarity sites. Mass-conserved activator-substrate (MCAS) models that describe polarity circuits develop multiple initial polarity sites, but then those sites engage in competition, leaving a single winner. Theoretical analyses predicted that competition would slow dramatically as GTPase concentrations at different polarity sites increase toward a 'saturation point', allowing polarity sites to coexist. Here, we test this prediction using budding yeast cells, and confirm that increasing the amount of key polarity proteins results in multiple polarity sites and simultaneous budding. Further, we elucidate a novel design principle whereby cells can switch from competition to equalization among polarity sites. These findings provide insight into how cells with diverse morphologies may determine the number of polarity sites.
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Affiliation(s)
- Jian-geng Chiou
- Department of Pharmacology and Cancer Biology, Duke University Medical CenterDurhamUnited States
| | - Kyle D Moran
- Department of Pharmacology and Cancer Biology, Duke University Medical CenterDurhamUnited States
| | - Daniel J Lew
- Department of Pharmacology and Cancer Biology, Duke University Medical CenterDurhamUnited States
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Cánovas-Márquez JT, Navarro-Mendoza MI, Pérez-Arques C, Lax C, Tahiri G, Pérez-Ruiz JA, Lorenzo-Gutiérrez D, Calo S, López-García S, Navarro E, Nicolás FE, Garre V, Murcia L. Role of the Non-Canonical RNAi Pathway in the Antifungal Resistance and Virulence of Mucorales. Genes (Basel) 2021; 12:genes12040586. [PMID: 33920552 PMCID: PMC8072676 DOI: 10.3390/genes12040586] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 04/12/2021] [Accepted: 04/14/2021] [Indexed: 12/19/2022] Open
Abstract
Mucorales are the causal agents for the lethal disease known as mucormycosis. Mortality rates of mucormycosis can reach up to 90%, due to the mucoralean antifungal drug resistance and the lack of effective therapies. A concerning urgency among the medical and scientific community claims to find targets for the development of new treatments. Here, we reviewed different studies describing the role and machinery of a novel non-canonical RNAi pathway (NCRIP) only conserved in Mucorales. Its non-canonical features are the independence of Dicer and Argonaute proteins. Conversely, NCRIP relies on RNA-dependent RNA Polymerases (RdRP) and an atypical ribonuclease III (RNase III). NCRIP regulates the expression of mRNAs by degrading them in a specific manner. Its mechanism binds dsRNA but only cuts ssRNA. NCRIP exhibits a diversity of functional roles. It represses the epimutational pathway and the lack of NCRIP increases the generation of drug resistant strains. NCRIP also regulates the control of retrotransposons expression, playing an essential role in genome stability. Finally, NCRIP regulates the response during phagocytosis, affecting the multifactorial process of virulence. These critical NCRIP roles in virulence and antifungal drug resistance, along with its exclusive presence in Mucorales, mark this pathway as a promising target to fight against mucormycosis.
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Affiliation(s)
- José Tomás Cánovas-Márquez
- Departamento de Genética y Microbiología, Facultad de Biología, Universidad de Murcia, 30100 Murcia, Spain; (J.T.C.-M.); (C.L.); (G.T.); (J.A.P.-R.); (D.L.-G.); (S.L.-G.); (E.N.); (F.E.N.); (V.G.)
| | - María Isabel Navarro-Mendoza
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA; (M.I.N.-M.); (C.P.-A.)
| | - Carlos Pérez-Arques
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA; (M.I.N.-M.); (C.P.-A.)
| | - Carlos Lax
- Departamento de Genética y Microbiología, Facultad de Biología, Universidad de Murcia, 30100 Murcia, Spain; (J.T.C.-M.); (C.L.); (G.T.); (J.A.P.-R.); (D.L.-G.); (S.L.-G.); (E.N.); (F.E.N.); (V.G.)
| | - Ghizlane Tahiri
- Departamento de Genética y Microbiología, Facultad de Biología, Universidad de Murcia, 30100 Murcia, Spain; (J.T.C.-M.); (C.L.); (G.T.); (J.A.P.-R.); (D.L.-G.); (S.L.-G.); (E.N.); (F.E.N.); (V.G.)
| | - José Antonio Pérez-Ruiz
- Departamento de Genética y Microbiología, Facultad de Biología, Universidad de Murcia, 30100 Murcia, Spain; (J.T.C.-M.); (C.L.); (G.T.); (J.A.P.-R.); (D.L.-G.); (S.L.-G.); (E.N.); (F.E.N.); (V.G.)
| | - Damaris Lorenzo-Gutiérrez
- Departamento de Genética y Microbiología, Facultad de Biología, Universidad de Murcia, 30100 Murcia, Spain; (J.T.C.-M.); (C.L.); (G.T.); (J.A.P.-R.); (D.L.-G.); (S.L.-G.); (E.N.); (F.E.N.); (V.G.)
| | - Silvia Calo
- School of Natural and Exact Sciences, Pontificia Universidad Católica Madre y Maestra, Santiago de los Caballeros 51033, Dominican Republic;
| | - Sergio López-García
- Departamento de Genética y Microbiología, Facultad de Biología, Universidad de Murcia, 30100 Murcia, Spain; (J.T.C.-M.); (C.L.); (G.T.); (J.A.P.-R.); (D.L.-G.); (S.L.-G.); (E.N.); (F.E.N.); (V.G.)
| | - Eusebio Navarro
- Departamento de Genética y Microbiología, Facultad de Biología, Universidad de Murcia, 30100 Murcia, Spain; (J.T.C.-M.); (C.L.); (G.T.); (J.A.P.-R.); (D.L.-G.); (S.L.-G.); (E.N.); (F.E.N.); (V.G.)
| | - Francisco Esteban Nicolás
- Departamento de Genética y Microbiología, Facultad de Biología, Universidad de Murcia, 30100 Murcia, Spain; (J.T.C.-M.); (C.L.); (G.T.); (J.A.P.-R.); (D.L.-G.); (S.L.-G.); (E.N.); (F.E.N.); (V.G.)
| | - Victoriano Garre
- Departamento de Genética y Microbiología, Facultad de Biología, Universidad de Murcia, 30100 Murcia, Spain; (J.T.C.-M.); (C.L.); (G.T.); (J.A.P.-R.); (D.L.-G.); (S.L.-G.); (E.N.); (F.E.N.); (V.G.)
| | - Laura Murcia
- Departamento de Genética y Microbiología, Facultad de Biología, Universidad de Murcia, 30100 Murcia, Spain; (J.T.C.-M.); (C.L.); (G.T.); (J.A.P.-R.); (D.L.-G.); (S.L.-G.); (E.N.); (F.E.N.); (V.G.)
- Correspondence:
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Mucoricin is a ricin-like toxin that is critical for the pathogenesis of mucormycosis. Nat Microbiol 2021; 6:313-326. [PMID: 33462434 PMCID: PMC7914224 DOI: 10.1038/s41564-020-00837-0] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 11/20/2020] [Indexed: 01/28/2023]
Abstract
Fungi of the order Mucorales cause mucormycosis, a lethal infection with an incompletely understood pathogenesis. We demonstrate that Mucorales fungi produce a toxin, which plays a central role in virulence. Polyclonal antibodies against this toxin inhibit its ability to damage human cells in vitro and prevent hypovolemic shock, organ necrosis and death in mice with mucormycosis. Inhibition of the toxin in Rhizopus delemar through RNA interference compromises the ability of the fungus to damage host cells and attenuates virulence in mice. This 17 kDa toxin has structural and functional features of the plant toxin ricin, including the ability to inhibit protein synthesis through its N-glycosylase activity, the existence of a motif that mediates vascular leak and a lectin sequence. Antibodies against the toxin inhibit R. delemar- or toxin-mediated vascular permeability in vitro and cross react with ricin. A monoclonal anti-ricin B chain antibody binds to the toxin and also inhibits its ability to cause vascular permeability. Therefore, we propose the name 'mucoricin' for this toxin. Not only is mucoricin important in the pathogenesis of mucormycosis but our data suggest that a ricin-like toxin is produced by organisms beyond the plant and bacterial kingdoms. Importantly, mucoricin should be a promising therapeutic target.
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Kijpornyongpan T, Aime MC. Investigating the Smuts: Common Cues, Signaling Pathways, and the Role of MAT in Dimorphic Switching and Pathogenesis. J Fungi (Basel) 2020; 6:jof6040368. [PMID: 33339287 PMCID: PMC7766764 DOI: 10.3390/jof6040368] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 12/10/2020] [Accepted: 12/14/2020] [Indexed: 12/11/2022] Open
Abstract
The corn smut fungus Ustilago maydis serves as a model species for studying fungal dimorphism and its role in phytopathogenic development. The pathogen has two growth phases: a saprobic yeast phase and a pathogenic filamentous phase. Dimorphic transition of U. maydis involves complex processes of signal perception, mating, and cellular reprogramming. Recent advances in improvement of reference genomes, high-throughput sequencing and molecular genetics studies have been expanding research in this field. However, the biology of other non-model species is frequently overlooked. This leads to uncertainty regarding how much of what is known in U. maydis is applicable to other dimorphic fungi. In this review, we will discuss dimorphic fungi in the aspects of physiology, reproductive biology, genomics, and molecular genetics. We also perform comparative analyses between U. maydis and other fungi in Ustilaginomycotina, the subphylum to which U. maydis belongs. We find that lipid/hydrophobicity is a potential common cue for dimorphic transition in plant-associated dimorphic fungi. However, genomic profiles alone are not adequate to explain dimorphism across different fungi.
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40
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Vellanki S, Garcia AE, Lee SC. Interactions of FK506 and Rapamycin With FK506 Binding Protein 12 in Opportunistic Human Fungal Pathogens. Front Mol Biosci 2020; 7:588913. [PMID: 33195437 PMCID: PMC7596385 DOI: 10.3389/fmolb.2020.588913] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Accepted: 09/22/2020] [Indexed: 12/19/2022] Open
Abstract
Over the past few decades advances in modern medicine have resulted in a global increase in the prevalence of fungal infections. Particularly people undergoing organ transplants or cancer treatments with a compromised immune system are at an elevated risk for lethal fungal infections such as invasive candidiasis, aspergillosis, cryptococcosis, etc. The emergence of drug resistance in fungal pathogens poses a serious threat to mankind and it is critical to identify new targets for the development of antifungals. Calcineurin and TOR proteins are conserved across eukaryotes including pathogenic fungi. Two small molecules FK506 and rapamycin bind to FKBP12 immunophilin and the resulting complexes (FK506-FKBP12 and rapamycin-FKBP12) target calcineurin and TOR, respectively in both humans and fungi. However, due to their immunosuppressive nature these drugs in the current form cannot be used as an antifungal. To overcome this, it is important to identify key differences between human and fungal FKBP12, calcineurin, and TOR proteins which will facilitate the development of new small molecules with higher affinity toward fungal components. The current review highlights FK506/rapamycin-FKBP12 interactions with calcineurin/TOR kinase in human and fungi, and development of non-immunosuppressive analogs of FK506, rapamycin, and novel small molecules in inhibition of fungal calcineurin and TOR kinase.
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Affiliation(s)
- Sandeep Vellanki
- South Texas Center for Emerging Infectious Diseases, Department of Biology, The University of Texas at San Antonio, San Antonio, TX, United States
| | - Alexis E Garcia
- South Texas Center for Emerging Infectious Diseases, Department of Biology, The University of Texas at San Antonio, San Antonio, TX, United States
| | - Soo Chan Lee
- South Texas Center for Emerging Infectious Diseases, Department of Biology, The University of Texas at San Antonio, San Antonio, TX, United States
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Xie Y, Loh ZY, Xue J, Zhou F, Sun J, Qiao Z, Jin S, Deng Y, Li H, Wang Y, Lu L, Gao Y, Miao Y. Orchestrated actin nucleation by the Candida albicans polarisome complex enables filamentous growth. J Biol Chem 2020; 295:14840-14854. [PMID: 32848016 DOI: 10.1074/jbc.ra120.013890] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 08/09/2020] [Indexed: 12/29/2022] Open
Abstract
Candida albicans is a dimorphic fungus that converts from a yeast form to a hyphae form during infection. This switch requires the formation of actin cable to coordinate polarized cell growth. It's known that nucleation of this cable requires a multiprotein complex localized at the tip called the polarisome, but the mechanisms underpinning this process were unclear. Here, we found that C. albicans Aip5, a homolog of polarisome component ScAip5 in Saccharomyces cerevisiae that nucleates actin polymerization and synergizes with the formin ScBni1, regulates actin assembly and hyphae growth synergistically with other polarisome proteins Bni1, Bud6, and Spa2. The C terminus of Aip5 binds directly to G-actin, Bni1, and the C-terminal of Bud6, which form the core of the nucleation complex to polymerize F-actin. Based on insights from structural biology and molecular dynamic simulations, we propose a possible complex conformation of the actin nucleation core, which provides cooperative positioning and supports the synergistic actin nucleation activity of a tri-protein complex Bni1-Bud6-Aip5. Together with known interactions of Bni1 with Bud6 and Aip5 in S. cerevisiae, our findings unravel molecular mechanisms of C. albicans by which the tri-protein complex coordinates the actin nucleation in actin cable assembly and hyphal growth, which is likely a conserved mechanism in different filamentous fungi and yeast.
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Affiliation(s)
- Ying Xie
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Zhi Yang Loh
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Jiao Xue
- School of Biological Sciences, Nanyang Technological University, Singapore; College of Life Science and Technology, Jinan University, Guangzhou, China; The College of Life Sciences, Northwest University, Xi'an, China
| | - Feng Zhou
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Jialin Sun
- School of Biological Sciences, Nanyang Technological University, Singapore; Institute of Molecular and Cell Biology, A*STAR, Singapore
| | - Zhu Qiao
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Shengyang Jin
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Yinyue Deng
- School of Pharmaceutical Sciences (Shenzhen), Sun Yat-sen University, Guangzhou, China
| | - Hongye Li
- College of Life Science and Technology, Jinan University, Guangzhou, China
| | - Yue Wang
- Institute of Molecular and Cell Biology, A*STAR, Singapore
| | - Lanyuan Lu
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Yonggui Gao
- School of Biological Sciences, Nanyang Technological University, Singapore; Institute of Molecular and Cell Biology, A*STAR, Singapore; NTU Institute of Structural Biology, Nanyang Technological University, Nanyang Drive, Singapore
| | - Yansong Miao
- School of Biological Sciences, Nanyang Technological University, Singapore.
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Increased Accumulation of Medium-Chain Fatty Acids by Dynamic Degradation of Long-Chain Fatty Acids in Mucor circinelloides. Genes (Basel) 2020; 11:genes11080890. [PMID: 32764225 PMCID: PMC7464202 DOI: 10.3390/genes11080890] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 07/22/2020] [Accepted: 07/27/2020] [Indexed: 12/12/2022] Open
Abstract
Concerns about global warming, fossil-fuel depletion, food security, and human health have promoted metabolic engineers to develop tools/strategies to overproduce microbial functional oils directly from renewable resources. Medium-chain fatty acids (MCFAs, C8–C12) have been shown to be important sources due to their diverse biotechnological importance, providing benefits ranging from functional lipids to uses in bio-fuel production. However, oleaginous microbes do not carry native pathways for the production of MCFAs, and therefore, diverse approaches have been adapted to compensate for the requirements of industrial demand. Mucor circinelloides is a promising organism for lipid production (15–36% cell dry weight; CDW) and the investigation of mechanisms of lipid accumulation; however, it mostly produces long-chain fatty acids (LCFAs). To address this challenge, we genetically modified strain M. circinelloides MU758, first by integrating heterologous acyl-ACP thioesterase (TE) into fatty acid synthase (FAS) complex and subsequently by modifying the β-oxidation pathway by disrupting the acyl-CoA oxidase (ACOX) and/or acyl-CoA thioesterase (ACOT) genes with a preference for medium-chain acyl-CoAs, to elevate the yield of MCFAs. The resultant mutant strains (M-1, M-2, and M-3, respectively) showed a significant increase in lipid production in comparison to the wild-type strain (WT). MCFAs in M-1 (47.45%) was sharply increased compared to the wild type strain (2.25%), and it was further increased in M-2 (60.09%) suggesting a negative role of ACOX in MCFAs production. However, MCFAs in M-3 were much decreased compared to M-1,suggesting a positive role of ACOT in MCFAs production. The M-2 strain showed maximum lipid productivity (~1800 milligram per liter per day or mg/L.d) and MCFAs productivity (~1100 mg/L.d). Taken together, this study elaborates on how the combination of two multidimensional approaches, TE gene over-expression and modification of the β-oxidation pathway via substantial knockout of specific ACOX gene, significantly increased the production of MCFAs. This synergistic approach ultimately offers a novel opportunity for synthetic/industrial biologists to increase the content of MCFAs.
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Valle-Maldonado MI, Patiño-Medina JA, Pérez-Arques C, Reyes-Mares NY, Jácome-Galarza IE, Ortíz-Alvarado R, Vellanki S, Ramírez-Díaz MI, Lee SC, Garre V, Meza-Carmen V. The heterotrimeric G-protein beta subunit Gpb1 controls hyphal growth under low oxygen conditions through the protein kinase A pathway and is essential for virulence in the fungus Mucor circinelloides. Cell Microbiol 2020; 22:e13236. [PMID: 32562333 DOI: 10.1111/cmi.13236] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 05/24/2020] [Accepted: 06/09/2020] [Indexed: 12/13/2022]
Abstract
Mucor circinelloides, a dimorphic opportunistic pathogen, expresses three heterotrimeric G-protein beta subunits (Gpb1, Gpb2 and Gpb3). The Gpb1-encoding gene is up-regulated during mycelial growth compared with that in the spore or yeast stage. gpb1 deletion mutation analysis revealed its relevance for an adequate development during the dimorphic transition and for hyphal growth under low oxygen concentrations. Infection assays in mice indicated a phenotype with considerably reduced virulence and tissue invasiveness in the deletion mutants (Δgpb1) and decreased host inflammatory response. This finding could be attributed to the reduced filamentous growth in animal tissues compared with that of the wild-type strain. Mutation in a regulatory subunit of cAMP-dependent protein kinase A (PKA) subunit (PkaR1) resulted in similar phenotypes to Δgpb1. The defects exhibited by the Δgpb1 strain were genetically suppressed by pkaR1 overexpression, indicating that the PKA pathway is controlled by Gpb1 in M. circinelloides. Moreover, during growth under low oxygen levels, cAMP levels were much higher in the Δgpb1 than in the wild-type strain, but similar to those in the ΔpkaR1 strain. These findings reveal that M. circinelloides possesses a signal transduction pathway through which the Gpb1 heterotrimeric G subunit and PkaR1 control mycelial growth in response to low oxygen levels.
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Affiliation(s)
- Marco Iván Valle-Maldonado
- Instituto de Investigaciones Químico Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Ciudad Universitaria, Morelia, Mexico
| | - José Alberto Patiño-Medina
- Instituto de Investigaciones Químico Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Ciudad Universitaria, Morelia, Mexico
| | - Carlos Pérez-Arques
- Departamento de Genética y Microbiología, Facultad de Biología, Universidad de Murcia, Murcia, Spain
| | - Nancy Yadira Reyes-Mares
- Instituto de Investigaciones Químico Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Ciudad Universitaria, Morelia, Mexico
| | | | - Rafael Ortíz-Alvarado
- Facultad de Quimico Farmacobiología, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Mexico
| | - Sandeep Vellanki
- South Texas Center for Emerging Infectious Diseases (STCEID), Department of Biology, The University of Texas at San Antonio, San Antonio, Texas, USA
| | - Martha Isela Ramírez-Díaz
- Instituto de Investigaciones Químico Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Ciudad Universitaria, Morelia, Mexico
| | - Soo Chan Lee
- South Texas Center for Emerging Infectious Diseases (STCEID), Department of Biology, The University of Texas at San Antonio, San Antonio, Texas, USA
| | - Victoriano Garre
- Departamento de Genética y Microbiología, Facultad de Biología, Universidad de Murcia, Murcia, Spain
| | - Víctor Meza-Carmen
- Instituto de Investigaciones Químico Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Ciudad Universitaria, Morelia, Mexico
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Arf-like proteins (Arl1 and Arl2) are involved in mitochondrial homeostasis in Mucor circinelloides. Fungal Biol 2020; 124:619-628. [DOI: 10.1016/j.funbio.2020.02.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 02/17/2020] [Accepted: 02/25/2020] [Indexed: 02/02/2023]
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Tornadic Shear Stress Induces a Transient, Calcineurin-Dependent Hypervirulent Phenotype in Mucorales Molds. mBio 2020; 11:mBio.01414-20. [PMID: 32605990 PMCID: PMC7327176 DOI: 10.1128/mbio.01414-20] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Trauma-related necrotizing myocutaneous mucormycosis (NMM) has a high morbidity and mortality in victims of combat-related injuries, geometeorological disasters, and severe burns. Inspired by the observation that several recent clusters of NMM have been associated with extreme mechanical forces (e.g., during tornados), we studied the impact of mechanical stress on Mucoralean biology and virulence in a Drosophila melanogaster infection model. In contrast to other experimental procedures to exert mechanical stress, tornadic shear challenge (TSC) by magnetic stirring induced a hypervirulent phenotype in several clinically relevant Mucorales species but not in Aspergillus or Fusarium Whereas fungal growth rates, morphogenesis, and susceptibility to noxious environments or phagocytes were not altered by TSC, soluble factors released in the supernatant of shear-challenged R. arrhizus spores rendered static spores hypervirulent. Consistent with a rapid decay of TSC-induced hypervirulence, minimal transcriptional changes were revealed by comparative RNA sequencing analysis of static and shear-challenged Rhizopus arrhizus However, inhibition of the calcineurin/heat shock protein 90 (hsp90) stress response circuitry by cyclosporine and tanespimycin abrogated the increased pathogenicity of R. arrhizus spores following TSC. Similarly, calcineurin loss-of-function mutants of Mucor circinelloides displayed no increased virulence capacity in flies after undergoing TSC. Collectively, these results establish that TSC induces hypervirulence specifically in Mucorales and point out the calcineurin/hsp90 pathway as a key orchestrator of this phenotype. Our findings invite future studies of topical calcineurin inhibitor treatment of wounds as an adjunct mitigation strategy for NMM following high-energy trauma.IMPORTANCE Given the limited efficacy of current medical treatments in trauma-related necrotizing mucormycosis, there is a dire need to better understand the Mucoralean pathophysiology in order to develop novel strategies to counteract fungal tissue invasion following severe trauma. Here, we describe that tornadic shear stress challenge transiently induces a hypervirulent phenotype in various pathogenic Mucorales species but not in other molds known to cause wound infections. Pharmacological and genetic inhibition of calcineurin signaling abrogated hypervirulence in shear stress-challenged Mucorales, encouraging further evaluation of (topical) calcineurin inhibitors to improve therapeutic outcomes of NMM after combat-related blast injuries or violent storms.
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Min K, Neiman AM, Konopka JB. Fungal Pathogens: Shape-Shifting Invaders. Trends Microbiol 2020; 28:922-933. [PMID: 32474010 DOI: 10.1016/j.tim.2020.05.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 04/24/2020] [Accepted: 05/05/2020] [Indexed: 12/11/2022]
Abstract
Fungal infections are on the rise due to new medical procedures that have increased the number of immune compromised patients, antibacterial antibiotics that disrupt the microbiome, and increased use of indwelling medical devices that provide sites for biofilm formation. Key to understanding the mechanisms of pathogenesis is to determine how fungal morphology impacts virulence strategies. For example, small budding cells use very different strategies to disseminate compared with long hyphal filaments. Furthermore, cell morphology must be monitored in the host, as many fungal pathogens change their shape to disseminate into new areas, acquire nutrients, and avoid attack by the immune system. This review describes the shape-shifting alterations in morphogenesis of human fungal pathogens and how they influence virulence strategies.
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Affiliation(s)
- Kyunghun Min
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, NY, USA
| | - Aaron M Neiman
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY, USA
| | - James B Konopka
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, NY, USA.
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47
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Lax C, Pérez-Arques C, Navarro-Mendoza MI, Cánovas-Márquez JT, Tahiri G, Pérez-Ruiz JA, Osorio-Concepción M, Murcia-Flores L, Navarro E, Garre V, Nicolás FE. Genes, Pathways, and Mechanisms Involved in the Virulence of Mucorales. Genes (Basel) 2020; 11:E317. [PMID: 32188171 PMCID: PMC7140881 DOI: 10.3390/genes11030317] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 03/06/2020] [Accepted: 03/09/2020] [Indexed: 12/19/2022] Open
Abstract
The order Mucorales is a group of ancient fungi with limited tools for gene manipulation. The main consequence of this manipulation unwillingness is the limited knowledge about its biology compared to other fungal groups. However, the emerging of mucormycosis, a fungal infection caused by Mucorales, is attracting the medical spotlight in recent years because the treatments available are not efficient in reducing the high mortality associated with this disease. The result of this renewed interest in Mucorales and mucormycosis is an extraordinarily productive effort to unveil their secrets during the last decade. In this review, we describe the most compelling advances related to the genetic study of virulence factors, pathways, and molecular mechanisms developed in these years. The use of a few genetic study models has allowed the characterization of virulence factors in Mucorales that were previously described in other pathogens, such as the uptake iron systems, the mechanisms of dimorphism, and azole resistances. More importantly, recent studies are identifying new genes and mechanisms controlling the pathogenic potential of Mucorales and their interactions with the host, offering new alternatives to develop specific strategies against mucormycosis.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Francisco Esteban Nicolás
- Departamento de Genética y Microbiología, Facultad de Biología, Universidad de Murcia, 30100 Murcia, Spain; (C.L.); (C.P.-A.); (M.I.N.-M.); (J.T.C.-M.); (G.T.); (J.A.P.-R.); (M.O.-C.); (L.M.-F.); (V.G.)
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48
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Park HS, Lee SC, Cardenas ME, Heitman J. Calcium-Calmodulin-Calcineurin Signaling: A Globally Conserved Virulence Cascade in Eukaryotic Microbial Pathogens. Cell Host Microbe 2020; 26:453-462. [PMID: 31600499 DOI: 10.1016/j.chom.2019.08.004] [Citation(s) in RCA: 83] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 06/29/2019] [Accepted: 08/02/2019] [Indexed: 12/19/2022]
Abstract
Calcium is an abundant intracellular ion, and calcium homeostasis plays crucial roles in several cellular processes. The calcineurin signaling cascade is one of the major pathways governed by intracellular calcium. Calcineurin, a conserved protein from yeast to humans, is a calcium-calmodulin-dependent serine-threonine-specific phosphatase that orchestrates cellular stress responses. In eukaryotic microbial pathogens, calcineurin controls essential virulence pathways, such as the ability to grow at host temperature, morphogenesis to enable invasive hyphal growth, drug tolerance and resistance, cell wall integrity, and sexual development. Therefore, the calcineurin cascade is an attractive target in drug development against eukaryotic pathogens. In the present review, we summarize and discuss the current knowledge on the roles of calcineurin in eukaryotic microbial pathogens, focusing on fungi and parasitic protists.
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Affiliation(s)
- Hee-Soo Park
- School of Food Science and Biotechnology, Institute of Agricultural Science and Technology, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Soo Chan Lee
- South Texas Center for Emerging Infectious Diseases (STCEID), Department of Biology, University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - Maria E Cardenas
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA.
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49
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Paul K, Saha C, Nag M, Mandal D, Naiya H, Sen D, Mitra S, Kumar M, Bose D, Mukherjee G, Naskar N, Lahiri S, Das Ghosh U, Tripathi S, Sarkar MP, Banerjee M, Kleinert A, Valentine AJ, Tripathy S, Sinharoy S, Seal A. A Tripartite Interaction among the Basidiomycete Rhodotorula mucilaginosa, N 2-Fixing Endobacteria, and Rice Improves Plant Nitrogen Nutrition. THE PLANT CELL 2020; 32:486-507. [PMID: 31757927 PMCID: PMC7008492 DOI: 10.1105/tpc.19.00385] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 10/25/2019] [Accepted: 11/19/2019] [Indexed: 05/21/2023]
Abstract
Nitrogen (N) limits crop yield, and improvement of N nutrition remains a key goal for crop research; one approach to improve N nutrition is identifying plant-interacting, N2-fixing microbes. Rhodotorula mucilaginosa JGTA-S1 is a basidiomycetous yeast endophyte of narrowleaf cattail (Typha angustifolia). JGTA-S1 could not convert nitrate or nitrite to ammonium but harbors diazotrophic (N2-fixing) endobacteria (Pseudomonas stutzeri) that allow JGTA-S1 to fix N2 and grow in a N-free environment; moreover, P. stutzeri dinitrogen reductase was transcribed in JGTA-S1 even under adequate N. Endobacteria-deficient JGTA-S1 had reduced fitness, which was restored by reintroducing P. stutzeri JGTA-S1 colonizes rice (Oryza sativa), significantly improving its growth, N content, and relative N-use efficiency. Endofungal P. stutzeri plays a significant role in increasing the biomass and ammonium content of rice treated with JGTA-S1; also, JGTA-S1 has better N2-fixing ability than free-living P. stutzeri and provides fixed N to the plant. Genes involved in N metabolism, N transporters, and NODULE INCEPTION-like transcription factors were upregulated in rice roots within 24 h of JGTA-S1 treatment. In association with rice, JGTA-S1 has a filamentous phase and P. stutzeri only penetrated filamentous JGTA-S1. Together, these results demonstrate an interkingdom interaction that improves rice N nutrition.
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Affiliation(s)
- Karnelia Paul
- Department of Biotechnology and Dr. B.C. Guha Centre for Genetic Engineering and Biotechnology, University of Calcutta, Kolkata 700019, India
| | - Chinmay Saha
- Department of Biotechnology and Dr. B.C. Guha Centre for Genetic Engineering and Biotechnology, University of Calcutta, Kolkata 700019, India
- Department of Endocrinology & Metabolism, Institute of Post Graduate Medical Education & Research and SSKM Hospital, Kolkata 700020, West Bengal, India
| | - Mayurakshi Nag
- Department of Biotechnology and Dr. B.C. Guha Centre for Genetic Engineering and Biotechnology, University of Calcutta, Kolkata 700019, India
| | - Drishti Mandal
- National Institute of Plant Genome Research, New Delhi 110067, India
| | - Haraprasad Naiya
- Department of Biotechnology and Dr. B.C. Guha Centre for Genetic Engineering and Biotechnology, University of Calcutta, Kolkata 700019, India
- ICAR-Indian Institute of Natural Resins and Gums Namkum, Ranchi 834010, Jharkhand, India
| | - Diya Sen
- Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Stockholm, SE 75007, Sweden
- Computational Genomics Laboratory, Structural Biology and Bioinformatics Division, Council of Scientific and Industrial Research-Indian Institute of Chemical Biology, Kolkata 700032, India
| | - Souvik Mitra
- Department of Botany, Darjeeling Government College, Darjeeling 734101, India
| | - Mohit Kumar
- Kusuma School of Biological Sciences, Indian Institute of Technology Delhi, New Delhi 110016, India
| | - Dipayan Bose
- Crystallography and Molecular Biology Division, Saha Institute of Nuclear Physics, Kolkata 700064, India
| | - Gairik Mukherjee
- Department of Biotechnology and Dr. B.C. Guha Centre for Genetic Engineering and Biotechnology, University of Calcutta, Kolkata 700019, India
| | - Nabanita Naskar
- Saha Institute of Nuclear Physics, Kolkata 700064, India
- Department of Environmental Science, University of Calcutta, Kolkata 700019, India
| | - Susanta Lahiri
- Saha Institute of Nuclear Physics, Kolkata 700064, India
| | - Upal Das Ghosh
- P.G. Department of Botany, Bidhannagar College, Kolkata 700026, India
| | - Sudipta Tripathi
- Agricultural Experimental Farm, Institute of Agricultural Science, University of Calcutta, Kolkata 700144, India
| | | | - Manidipa Banerjee
- Kusuma School of Biological Sciences, Indian Institute of Technology Delhi, New Delhi 110016, India
| | - Aleysia Kleinert
- Botany & Zoology Department, University of Stellenbosch Private Bag X1 Matieland 7602 South Africa
| | - Alexander J Valentine
- Botany & Zoology Department, University of Stellenbosch Private Bag X1 Matieland 7602 South Africa
| | - Sucheta Tripathy
- Computational Genomics Laboratory, Structural Biology and Bioinformatics Division, Council of Scientific and Industrial Research-Indian Institute of Chemical Biology, Kolkata 700032, India
| | - Senjuti Sinharoy
- National Institute of Plant Genome Research, New Delhi 110067, India
| | - Anindita Seal
- Department of Biotechnology and Dr. B.C. Guha Centre for Genetic Engineering and Biotechnology, University of Calcutta, Kolkata 700019, India
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50
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Vellanki S, Billmyre RB, Lorenzen A, Campbell M, Turner B, Huh EY, Heitman J, Lee SC. A Novel Resistance Pathway for Calcineurin Inhibitors in the Human-Pathogenic Mucorales Mucor circinelloides. mBio 2020; 11:e02949-19. [PMID: 31992620 PMCID: PMC6989107 DOI: 10.1128/mbio.02949-19] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 12/16/2019] [Indexed: 12/24/2022] Open
Abstract
Mucormycosis is an emerging lethal fungal infection in immunocompromised patients. Mucor circinelloides is a causal agent of mucormycosis and serves as a model system to understand genetics in Mucorales. Calcineurin is a conserved virulence factor in many pathogenic fungi, and calcineurin inhibition or deletion of the calcineurin regulatory subunit (CnbR) in Mucor results in a shift from hyphal to yeast growth. We analyzed 36 calcineurin inhibitor-resistant or bypass mutants that exhibited hyphal growth in the presence of calcineurin inhibitors or in the yeast-locked cnbRΔ mutant background without carrying any mutations in known calcineurin components. We found that a majority of the mutants had altered sequence in a gene, named here bycA (bypass of calcineurin). bycA encodes an amino acid permease. We verified that both the bycAΔ single mutant and the bycAΔ cnbRΔ double mutant are resistant to calcineurin inhibitor FK506, thereby demonstrating a novel mechanism of resistance against calcineurin inhibitors. We also found that the level of expression of bycA was significantly higher in the wild-type strain treated with FK506 and in the cnbRΔ mutants but was significantly lower in the wild-type strain without FK506 treatment. These findings suggest that bycA is a negative regulator of hyphal growth and/or a positive regulator of yeast growth in Mucor and that calcineurin suppresses expression of the bycA gene at the mRNA level to promote hyphal growth. BycA is involved in the Mucor hypha-yeast transition as our data demonstrate positive correlations among bycA expression, protein kinase A activity, and Mucor yeast growth. Also, calcineurin, independently of its role in morphogenesis, contributes to virulence traits, including phagosome maturation blockade, host cell damages, and proangiogenic growth factor induction during interactions with hosts.IMPORTANCEMucor is intrinsically resistant to most known antifungals, which makes mucormycosis treatment challenging. Calcineurin is a serine/threonine phosphatase that is widely conserved across eukaryotes. When calcineurin function is inhibited in Mucor, growth shifts to a less virulent yeast growth form, which makes calcineurin an attractive target for development of new antifungal drugs. Previously, we identified two distinct mechanisms through which Mucor can become resistant to calcineurin inhibitors involving Mendelian mutations in the gene for FKBP12, including mechanisms corresponding to calcineurin A or B subunits and epimutations silencing the FKBP12 gene. Here, we identified a third novel mechanism where loss-of-function mutations in the amino acid permease corresponding to the bycA gene contribute to resistance against calcineurin inhibitors. When calcineurin activity is absent, BycA can activate protein kinase A (PKA) to promote yeast growth via a cAMP-independent pathway. Our data also show that calcineurin activity contributes to host-pathogen interactions primarily in the pathogenesis of Mucor.
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Affiliation(s)
- Sandeep Vellanki
- South Texas Center for Emerging Infectious Diseases (STCEID), Department of Biology, The University of Texas at San Antonio, San Antonio, Texas, USA
| | - R Blake Billmyre
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, USA
| | - Alejandra Lorenzen
- South Texas Center for Emerging Infectious Diseases (STCEID), Department of Biology, The University of Texas at San Antonio, San Antonio, Texas, USA
| | - Micaela Campbell
- South Texas Center for Emerging Infectious Diseases (STCEID), Department of Biology, The University of Texas at San Antonio, San Antonio, Texas, USA
| | - Broderick Turner
- South Texas Center for Emerging Infectious Diseases (STCEID), Department of Biology, The University of Texas at San Antonio, San Antonio, Texas, USA
| | - Eun Young Huh
- South Texas Center for Emerging Infectious Diseases (STCEID), Department of Biology, The University of Texas at San Antonio, San Antonio, Texas, USA
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, USA
| | - Soo Chan Lee
- South Texas Center for Emerging Infectious Diseases (STCEID), Department of Biology, The University of Texas at San Antonio, San Antonio, Texas, USA
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