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Clavijo-Giraldo DM, Pérez-García LA, Hernández-Chávez MJ, Martínez-Duncker I, Mora-Montes HM. Contribution of N-Linked Mannosylation Pathway to Candida parapsilosis and Candida tropicalis Biofilm Formation. Infect Drug Resist 2023; 16:6843-6857. [PMID: 37908782 PMCID: PMC10614665 DOI: 10.2147/idr.s431745] [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: 07/21/2023] [Accepted: 10/18/2023] [Indexed: 11/02/2023] Open
Abstract
Background Mycoses are a growing threat to human health, and systemic candidiasis caused by Candida parapsilosis and Candida tropicalis is frequent in immunocompromised patients. Biofilm formation is a virulence factor found in these organisms, as sessile cells adhere to surfaces, the stratification and production of extracellular matrix provides protection and resistance to antifungal drugs. Previous evidence indicated that the N-linked mannosylation pathway is relevant to C. albicans biofilms, but its contribution to other species remains unknown. Methods C. parapsilosis and C. tropicalis och1∆ mutants, which have a disrupted N-linked mannosylation pathway, were used to form biofilms. In addition, wild-type and mutant cells were also treated to remove N-linked mannans or block this pathway. Biofilms were analyzed by quantifying the included fungal biomass, and extracellular matrix components. Moreover, gene expression and secreted hydrolytic enzymes were also quantified in these biofilms. Results The och1∆ mutants showed a reduced ability to form biofilms in both fungal species when compared to the wild-type and control strains. This observation was confirmed by trimming N-linked mannans from walls or blocking the pathway with tunicamycin B. According to this observation, mutant, and treated cells showed an altered composition of the extracellular matrix and increased susceptibility to antifungal drugs when compared to control or untreated cells. The gene expression of secreted virulence factors, such as aspartyl proteinases and phospholipases, was normal in all the tested cells but the secreted activity was reduced, suggesting a defect in the secretory pathway, which was later confirmed by treating cells with brefeldin A. Conclusion Proper N-linked mannosylation is required for biofilm formation in both C. parapsilosis and C. tropicalis. Disruption of this posttranslational modification affected the secretory pathway, offering a link between glycosylation and biofilm formation.
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Affiliation(s)
| | - Luis A Pérez-García
- Departamento de Biología, Universidad de Guanajuato, Guanajuato, Gto., México
- Facultad de Estudios Profesionales Zona Huasteca, Universidad Autónoma de San Luis Potosí, Ciudad Valles, San Luis Potosí, México
| | | | - Iván Martínez-Duncker
- Laboratorio de Glicobiología Humana y Diagnóstico Molecular; Universidad Autónoma del Estado de Morelos, Cuernavaca, Morelos, México
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Orłowska M, Barua D, Piłsyk S, Muszewska A. Fucose as a nutrient ligand for Dikarya and a building block of early diverging lineages. IMA Fungus 2023; 14:17. [PMID: 37670396 PMCID: PMC10481521 DOI: 10.1186/s43008-023-00123-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 08/07/2023] [Indexed: 09/07/2023] Open
Abstract
Fucose is a deoxyhexose sugar present and studied in mammals. The process of fucosylation has been the primary focus in studies relating to fucose in animals due to the presence of fucose in Lewis antigens. Very few studies have reported its presence in Fungi, mostly in Mucoromycotina. The constitution of 25% and 12% of this sugar in the carbohydrates of cell wall in the respective Umbelopsis and Mucorales strains boosts the need to bridge the gap of knowledge on fucose metabolism across the fungal tree of life. In the absence of a network map involving fucose proteins, we carried out an in-silico approach to construct the fucose metabolic map in Fungi. We analyzed the taxonomic distribution of 85 protein families in Fungi including diverse early diverging fungal lineages. The expression of fucose-related protein-coding genes proteins was validated with the help of transcriptomic data originating from representatives of early diverging fungi. We found proteins involved in several metabolic activities apart from fucosylation such as synthesis, transport and binding. Most of the identified protein families are shared with Metazoa suggesting an ancestral origin in Opisthokonta. However, the overall complexity of fucose metabolism is greater in Metazoa than in Fungi. Massive gene loss has shaped the evolutionary history of these metabolic pathways, leading to a repeated reduction of these pathways in most yeast-forming lineages. Our results point to a distinctive mode of utilization of fucose among fungi belonging to Dikarya and the early diverging lineages. We speculate that, while Dikarya used fucose as a source of nutrients for metabolism, the early diverging group of fungi depended on fucose as a building block and signaling compound.
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Affiliation(s)
- Małgorzata Orłowska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, 02-106, Warsaw, Poland.
- Institute of Evolutionary Biology, Faculty of Biology, Biological and Chemical Research Centre, University of Warsaw, Zwirki i Wigury 101, 02-089, Warsaw, Poland.
| | - Drishtee Barua
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, 02-106, Warsaw, Poland
| | - Sebastian Piłsyk
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, 02-106, Warsaw, Poland
| | - Anna Muszewska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, 02-106, Warsaw, Poland.
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3
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López-Ramírez LA, Martínez-Duncker I, Márquez-Márquez A, Vargas-Macías AP, Mora-Montes HM. Silencing of ROT2, the Encoding Gene of the Endoplasmic Reticulum Glucosidase II, Affects the Cell Wall and the Sporothrix schenckii-Host Interaction. J Fungi (Basel) 2022; 8:1220. [PMID: 36422041 PMCID: PMC9692468 DOI: 10.3390/jof8111220] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 11/11/2022] [Accepted: 11/17/2022] [Indexed: 08/01/2023] Open
Abstract
Sporothrix schenckii is a member of the Sporothrix pathogenic clade and one of the most common etiological agents of sporotrichosis, a subcutaneous fungal infection that affects both animal and human beings. Like other fungal pathogens, the Sporothrix cell wall is composed of structural polysaccharides and glycoproteins that are covalently modified with both N-linked and O-linked glycans. Thus far, little is known about the N-linked glycosylation pathway in this organism or its contribution to cell wall composition and interaction with the host. Here, we silenced ROT2, which encodes the catalytic subunit of the endoplasmic reticulum α-glucosidase II, a processing enzyme key for the N-linked glycan core processing. Silencing of ROT2 led to the accumulation of the Glc2Man9GlcNAC2 glycan core at the cell wall and a reduction in the total content of N-linked glycans found in the wall. However, the highly silenced mutants showed a compensatory mechanism with increased content of cell wall O-linked glycans. The phenotype of mutants with intermediate levels of ROT2 silencing was more informative, as they showed changes in the cell wall composition and exposure of β-1.3-glucans and chitin at the cell surface. Furthermore, the ability to stimulate cytokine production by human mononuclear cells was affected, along with the phagocytosis by human monocyte-derived macrophages, in a mannose receptor-, complement receptor 3-, and TLR4-dependent stimulation. In an insect model of experimental sporotrichosis, these mutant cells showed virulence attenuation. In conclusion, S. schenckii ROT2 is required for proper N-linked glycosylation, cell wall organization and composition, and interaction with the host.
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Affiliation(s)
- Luz A. López-Ramírez
- Departamento de Biología, División de Ciencias Naturales y Exactas, Campus Guanajuato, Universidad de Guanajuato, Noria Alta s/n, col. Noria Alta, C.P., Guanajuato 36050, Mexico
| | - Iván Martínez-Duncker
- Laboratorio de Glicobiología Humana y Diagnóstico Molecular, Centro de Investigación en Dinámica Celular, Instituto de Investigación en Ciencias Básicas y Aplicadas, Universidad Autónoma del Estado de Morelos, Cuernavaca 62209, Mexico
| | - Anayeli Márquez-Márquez
- Departamento de Biología, División de Ciencias Naturales y Exactas, Campus Guanajuato, Universidad de Guanajuato, Noria Alta s/n, col. Noria Alta, C.P., Guanajuato 36050, Mexico
| | - Ana P. Vargas-Macías
- Departamento de Biología, División de Ciencias Naturales y Exactas, Campus Guanajuato, Universidad de Guanajuato, Noria Alta s/n, col. Noria Alta, C.P., Guanajuato 36050, Mexico
| | - Héctor M. Mora-Montes
- Departamento de Biología, División de Ciencias Naturales y Exactas, Campus Guanajuato, Universidad de Guanajuato, Noria Alta s/n, col. Noria Alta, C.P., Guanajuato 36050, Mexico
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4
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Dean N, Jones R, DaSilva J, Chionchio G, Ng H. The Mnn10/Anp1-dependent N-linked outer chain glycan is dispensable for Candida albicans cell wall integrity. Genetics 2022; 221:6554200. [PMID: 35333306 PMCID: PMC9071539 DOI: 10.1093/genetics/iyac048] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 03/11/2022] [Indexed: 11/13/2022] Open
Abstract
Candida albicans cell wall glycoproteins, and in particular their mannose-rich glycans, are important for maintaining cellular integrity as well as host recognition, adhesion, and immunomodulation. The asparagine (N)-linked mannose outer chain of these glycoproteins is produced by Golgi mannosyltransferases (MTases). The outer chain is composed of a linear backbone of ∼50 α1,6-linked mannoses, which acts as a scaffold for addition of ∼150 or more mannoses in other linkages. Here, we describe the characterization of C. albicans OCH1, MNN9, VAN1, ANP1, MNN10, and MNN11, which encode the conserved Golgi MTases that sequentially catalyze the α1,6 mannose outer chain backbone. Candida albicans och1Δ/Δ, mnn9Δ/Δ, and van1Δ/Δ mutants block the earliest steps of backbone synthesis and like their Saccharomyces cerevisiae counterparts, have severe cell wall and growth phenotypes. Unexpectedly, and in stark contrast to S. cerevisiae, loss of Anp1, Mnn10, or Mnn11, which together synthesize most of the backbone, have no obvious deleterious phenotypes. These mutants were unaffected in cell morphology, growth, drug sensitivities, hyphal formation, and macrophage recognition. Analyses of secreted glycosylation reporters demonstrated that anp1Δ/Δ, mnn10Δ/Δ, and mnn11Δ/Δ strains accumulate glycoproteins with severely truncated N-glycan chains. This hypo-mannosylation did not elicit increased chitin deposition in the cell wall, which in other yeast and fungi is a key compensatory response to cell wall integrity breaches. Thus, C. albicans has evolved an alternate mechanism to adapt to cell wall weakness when N-linked mannan levels are reduced.
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Affiliation(s)
- Neta Dean
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794-5215, USA
- Corresponding author: Department of Biochemistry and Cell Biology, Life Sciences Bldg Room 310, Stony Brook University, Stony Brook, NY 11794-5215, USA.
| | - Rachel Jones
- Department of Anesthesiology, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, NY 10467, USA
| | - Justin DaSilva
- Laboratory of Retrovirology, The Rockefeller University, New York, NY 10065, USA
| | - Gregory Chionchio
- Donald and Barbara Zucker School of Medicine, Hofstra/Northwell, Hempstead, NY 11549, USA
| | - Henry Ng
- Department of Physiology, University of California, San Francisco, CA 94143, USA
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5
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Role of Protein Glycosylation in Interactions of Medically Relevant Fungi with the Host. J Fungi (Basel) 2021; 7:jof7100875. [PMID: 34682296 PMCID: PMC8541085 DOI: 10.3390/jof7100875] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 10/08/2021] [Accepted: 10/11/2021] [Indexed: 01/09/2023] Open
Abstract
Protein glycosylation is a highly conserved post-translational modification among organisms. It plays fundamental roles in many biological processes, ranging from protein trafficking and cell adhesion to host–pathogen interactions. According to the amino acid side chain atoms to which glycans are linked, protein glycosylation can be divided into two major categories: N-glycosylation and O-glycosylation. However, there are other types of modifications such as the addition of GPI to the C-terminal end of the protein. Besides the importance of glycoproteins in biological functions, they are a major component of the fungal cell wall and plasma membrane and contribute to pathogenicity, virulence, and recognition by the host immunity. Given that this structure is absent in host mammalian cells, it stands as an attractive target for developing selective compounds for the treatment of fungal infections. This review focuses on describing the relationship between protein glycosylation and the host–immune interaction in medically relevant fungal species.
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6
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Hameed S, Hans S, Singh S, Dhiman R, Monasky R, Pandey RP, Thangamani S, Fatima Z. Revisiting the Vital Drivers and Mechanisms of β-Glucan Masking in Human Fungal Pathogen, Candida albicans. Pathogens 2021; 10:942. [PMID: 34451406 PMCID: PMC8399646 DOI: 10.3390/pathogens10080942] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 07/14/2021] [Accepted: 07/22/2021] [Indexed: 12/31/2022] Open
Abstract
Among the several human fungal pathogens, Candida genus represents one of the most implicated in the clinical scenario. There exist several distinctive features that govern the establishment of Candida infections in addition to their capacity to adapt to multiple stress conditions inside humans which also include evasion of host immune responses. The complex fungal cell wall of the prevalent pathogen, Candida albicans, is one of the main targets of antifungal drugs and recognized by host immune cells. The wall consists of tiered arrangement of an outer thin but dense covering of mannan and inner buried layers of β-glucan and chitin. However, the pathogenic fungi adopt strategies to evade immune recognition by masking these molecules. This capacity to camouflage the immunogenic polysaccharide β-glucan from the host is a key virulence factor of C. albicans. The present review is an attempt to collate various underlying factors and mechanisms involved in Candida β-glucan masking from the available pool of knowledge and provide a comprehensive understanding. This will further improve therapeutic approaches to candidiasis by identifying new antifungal targets that blocks fungal immune evasion.
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Affiliation(s)
- Saif Hameed
- Amity Institute of Biotechnology, Amity University Haryana, Gurugram 122413, India; (S.H.); (S.H.); (S.S.)
| | - Sandeep Hans
- Amity Institute of Biotechnology, Amity University Haryana, Gurugram 122413, India; (S.H.); (S.H.); (S.S.)
| | - Shweta Singh
- Amity Institute of Biotechnology, Amity University Haryana, Gurugram 122413, India; (S.H.); (S.H.); (S.S.)
| | - Ruby Dhiman
- Centre for Drug Design Discovery and Development (C4D), SRM University, Sonepat 131029, India; (R.D.); (R.P.P.)
| | - Ross Monasky
- Department of Pathology and Population Medicine, College of Veterinary Medicine, Midwestern University, 19555 N. 59th Ave., Glendale, AZ 85308, USA; (R.M.); (S.T.)
| | - Ramendra Pati Pandey
- Centre for Drug Design Discovery and Development (C4D), SRM University, Sonepat 131029, India; (R.D.); (R.P.P.)
| | - Shankar Thangamani
- Department of Pathology and Population Medicine, College of Veterinary Medicine, Midwestern University, 19555 N. 59th Ave., Glendale, AZ 85308, USA; (R.M.); (S.T.)
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, IN 47906, USA
| | - Zeeshan Fatima
- Amity Institute of Biotechnology, Amity University Haryana, Gurugram 122413, India; (S.H.); (S.H.); (S.S.)
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7
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Tamez-Castrellón AK, Romeo O, García-Carnero LC, Lozoya-Pérez NE, Mora-Montes HM. Virulence Factors in Sporothrix schenckii, One of the Causative Agents of Sporotrichosis. Curr Protein Pept Sci 2021; 21:295-312. [PMID: 31589121 DOI: 10.2174/1389203720666191007103004] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 08/02/2019] [Accepted: 08/08/2019] [Indexed: 11/22/2022]
Abstract
Sporothrix schenckii is one of the etiological agents of sporotrichosis, a fungal infection distributed worldwide. Both, the causative organism and the disease have currently received limited attention by the medical mycology community, most likely because of the low mortality rates associated with it. Nonetheless, morbidity is high in endemic regions and the versatility of S. schenckii to cause zoonosis and sapronosis has attracted attention. Thus far, virulence factors associated with this organism are poorly described. Here, comparing the S. schenckii genome sequence with other medically relevant fungi, genes involved in morphological change, cell wall synthesis, immune evasion, thermotolerance, adhesion, biofilm formation, melanin production, nutrient uptake, response to stress, extracellular vesicle formation, and toxin production are predicted and discussed as putative virulence factors in S. schenckii.
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Affiliation(s)
- Alma K Tamez-Castrellón
- Departamento de Biología, División de Ciencias Naturales y Exactas, Campus Guanajuato, Universidad de Guanajuato, Noria Alta s/n, col. Noria Alta, C.P. 36050, Guanajuato, Gto., Mexico
| | - Orazio Romeo
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Messina, Italy
| | - Laura C García-Carnero
- Departamento de Biología, División de Ciencias Naturales y Exactas, Campus Guanajuato, Universidad de Guanajuato, Noria Alta s/n, col. Noria Alta, C.P. 36050, Guanajuato, Gto., Mexico
| | - Nancy E Lozoya-Pérez
- Departamento de Biología, División de Ciencias Naturales y Exactas, Campus Guanajuato, Universidad de Guanajuato, Noria Alta s/n, col. Noria Alta, C.P. 36050, Guanajuato, Gto., Mexico
| | - Héctor M Mora-Montes
- Departamento de Biología, División de Ciencias Naturales y Exactas, Campus Guanajuato, Universidad de Guanajuato, Noria Alta s/n, col. Noria Alta, C.P. 36050, Guanajuato, Gto., Mexico
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8
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Evans DeWald L, Starr C, Butters T, Treston A, Warfield KL. Iminosugars: A host-targeted approach to combat Flaviviridae infections. Antiviral Res 2020; 184:104881. [PMID: 32768411 PMCID: PMC7405907 DOI: 10.1016/j.antiviral.2020.104881] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 07/07/2020] [Accepted: 07/13/2020] [Indexed: 12/12/2022]
Abstract
N-linked glycosylation is the most common form of protein glycosylation and is required for the proper folding, trafficking, and/or receptor binding of some host and viral proteins. As viruses lack their own glycosylation machinery, they are dependent on the host's machinery for these processes. Certain iminosugars are known to interfere with the N-linked glycosylation pathway by targeting and inhibiting α-glucosidases I and II in the endoplasmic reticulum (ER). Perturbing ER α-glucosidase function can prevent these enzymes from removing terminal glucose residues on N-linked glycans, interrupting the interaction between viral glycoproteins and host chaperone proteins that is necessary for proper folding of the viral protein. Iminosugars have demonstrated broad-spectrum antiviral activity in vitro and in vivo against multiple viruses. This review discusses the broad activity of iminosugars against Flaviviridae. Iminosugars have shown favorable activity against multiple members of the Flaviviridae family in vitro and in murine models of disease, although the activity and mechanism of inhibition can be virus-specfic. While iminosugars are not currently approved for the treatment of viral infections, their potential use as future host-targeted antiviral (HTAV) therapies continues to be investigated.
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Affiliation(s)
| | - Chloe Starr
- Emergent BioSolutions, Gaithersburg, MD, 20879, USA
| | | | | | - Kelly L. Warfield
- Emergent BioSolutions, Gaithersburg, MD, 20879, USA,Corresponding author. 400 Professional Drive, Gaithersburg, MD, 20879, USA
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9
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Gómez-Gaviria M, Lozoya-Pérez NE, Staniszewska M, Franco B, Niño-Vega GA, Mora-Montes HM. Loss of Kex2 Affects the Candida albicans Cell Wall and Interaction with Innate Immune Cells. J Fungi (Basel) 2020; 6:jof6020057. [PMID: 32365492 PMCID: PMC7344602 DOI: 10.3390/jof6020057] [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] [Received: 04/14/2020] [Revised: 04/27/2020] [Accepted: 04/28/2020] [Indexed: 12/18/2022] Open
Abstract
The secretory pathway in Candida albicans involves the protein translocation into the lumen of the endoplasmic reticulum and transport to the Golgi complex, where proteins undergo posttranslational modifications, including glycosylation and proteolysis. The Golgi-resident Kex2 protease is involved in such processing and disruption of its encoding gene affected virulence and dimorphism. These previous studies were performed using cells without URA3 or with URA3 ectopically placed into the KEX2 locus. Since these conditions are known to affect the cellular fitness and the host-fungus interaction, here we generated a kex2Δ null mutant strain with URA3 placed into the neutral locus RPS1. The characterization of this strain showed defects in the cell wall composition, with a reduction in the N-linked mannan content, and the increment in the levels of O-linked mannans, chitin, and β-glucans. The defects in the mannan content are likely linked to changes in Golgi-resident enzymes, as the α-1,2-mannosyltransferase and α-1,6-mannosyltransferase activities were incremented and reduced, respectively. The mutant cells also showed reduced ability to stimulate cytokine production and phagocytosis by human mononuclear cells and macrophages, respectively. Collectively, these data showed that loss of Kex2 affected the cell wall composition, the protein glycosylation pathways, and interaction with innate immune cells.
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Affiliation(s)
- Manuela Gómez-Gaviria
- Departamento de Biología, División de Ciencias Naturales y Exactas, Campus Guanajuato, Universidad de Guanajuato, Guanajuato Gto 36050, Mexico; (M.G.-G.); (N.E.L.-P.); (B.F.); (G.A.N.-V.)
| | - Nancy E. Lozoya-Pérez
- Departamento de Biología, División de Ciencias Naturales y Exactas, Campus Guanajuato, Universidad de Guanajuato, Guanajuato Gto 36050, Mexico; (M.G.-G.); (N.E.L.-P.); (B.F.); (G.A.N.-V.)
| | - Monika Staniszewska
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland;
| | - Bernardo Franco
- Departamento de Biología, División de Ciencias Naturales y Exactas, Campus Guanajuato, Universidad de Guanajuato, Guanajuato Gto 36050, Mexico; (M.G.-G.); (N.E.L.-P.); (B.F.); (G.A.N.-V.)
| | - Gustavo A. Niño-Vega
- Departamento de Biología, División de Ciencias Naturales y Exactas, Campus Guanajuato, Universidad de Guanajuato, Guanajuato Gto 36050, Mexico; (M.G.-G.); (N.E.L.-P.); (B.F.); (G.A.N.-V.)
| | - Hector M. Mora-Montes
- Departamento de Biología, División de Ciencias Naturales y Exactas, Campus Guanajuato, Universidad de Guanajuato, Guanajuato Gto 36050, Mexico; (M.G.-G.); (N.E.L.-P.); (B.F.); (G.A.N.-V.)
- Correspondence: ; Tel.: +52-473-732-0006 (ext. 8193)
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The Role of Secretory Pathways in Candida albicans Pathogenesis. J Fungi (Basel) 2020; 6:jof6010026. [PMID: 32102426 PMCID: PMC7151058 DOI: 10.3390/jof6010026] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2020] [Revised: 02/19/2020] [Accepted: 02/20/2020] [Indexed: 12/17/2022] Open
Abstract
Candida albicans is a fungus that is a commensal organism and a member of the normal human microbiota. It has the ability to transition into an opportunistic invasive pathogen. Attributes that support pathogenesis include secretion of virulence-associated proteins, hyphal formation, and biofilm formation. These processes are supported by secretion, as defined in the broad context of membrane trafficking. In this review, we examine the role of secretory pathways in Candida virulence, with a focus on the model opportunistic fungal pathogen, Candida albicans.
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11
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Alves R, Kastora SL, Gomes-Gonçalves A, Azevedo N, Rodrigues CF, Silva S, Demuyser L, Van Dijck P, Casal M, Brown AJP, Henriques M, Paiva S. Transcriptional responses of Candida glabrata biofilm cells to fluconazole are modulated by the carbon source. NPJ Biofilms Microbiomes 2020; 6:4. [PMID: 31993211 PMCID: PMC6978337 DOI: 10.1038/s41522-020-0114-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 12/20/2019] [Indexed: 12/21/2022] Open
Abstract
Candida glabrata is an important human fungal pathogen known to trigger serious infections in immune-compromised individuals. Its ability to form biofilms, which exhibit high tolerance to antifungal treatments, has been considered as an important virulence factor. However, the mechanisms involving antifungal resistance in biofilms and the impact of host niche environments on these processes are still poorly defined. In this study, we performed a whole-transcriptome analysis of C. glabrata biofilm cells exposed to different environmental conditions and constraints in order to identify the molecular pathways involved in fluconazole resistance and understand how acidic pH niches, associated with the presence of acetic acid, are able to modulate these responses. We show that fluconazole treatment induces gene expression reprogramming in a carbon source and pH-dependent manner. This is particularly relevant for a set of genes involved in DNA replication, ergosterol, and ubiquinone biosynthesis. We also provide additional evidence that the loss of mitochondrial function is associated with fluconazole resistance, independently of the growth condition. Lastly, we propose that C. glabrata Mge1, a cochaperone involved in iron metabolism and protein import into the mitochondria, is a key regulator of fluconazole susceptibility during carbon and pH adaptation by reducing the metabolic flux towards toxic sterol formation. These new findings suggest that different host microenvironments influence directly the physiology of C. glabrata, with implications on how this pathogen responds to antifungal treatment. Our analyses identify several pathways that can be targeted and will potentially prove to be useful for developing new antifungals to treat biofilm-based infections.
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Grants
- MR/M026663/1 Medical Research Council
- MR/N006364/1 Medical Research Council
- MR/N006364/2 Medical Research Council
- This study was supported by the Portuguese National Funding Agency for Science, Research and Technology FCT (grant PTDC/BIAMIC/5184/2014). RA received FCT PhD fellowship (PD/BD/113813/2015). The authors gratefully acknowledge Edinburgh Genomics for RNA-Seq library preparation and sequencing. The work on CBMA was supported by the strategic program UID/BIA/04050/2013 (POCI-01-0145-FEDER-007569). The work on CEB was supported by PEst-OE/EQB/LA0023/2013, from FCT, “BioHealth - Biotechnology and Bioengineering approaches to improve health quality", Ref. NORTE-07-0124-FEDER-000027, co-funded by the Programa Operacional Regional do Norte (ON.2 – O Novo Norte), QREN, FEDER and the project “Consolidating Research Expertize and Resources on Cellular and Molecular Biotechnology at CEB/IBB”, Ref. FCOMP-01-0124-FEDER-027462. The work in Aberdeen was also supported by the European Research Council through the advanced grant “STRIFE” (C-2009-AdG-249793), by the UK Medical Research Council (MR/M026663/1) and by the Medical Research Council Center for Medical Mycology and the University of Aberdeen (MR/N006364/1). The work at KU Leuven was supported by the Federation of European Biochemical Societies (FEBS) through a short-term fellowship awarded to RA and by the Fund for Scientific Research Flanders (FWO; WO.009.16N).
- Federation of European Biochemical Societies (FEBS)
- Strategic program UID/BIA/04050/2013 (POCI-01-0145-FEDER-007569)
- European Research Council through the advanced grant “STRIFE” (C-2009-AdG-249793), UK Medical Research Council (MR/M026663/1) and Medical Research Council Center for Medical Mycology and the University of Aberdeen (MR/N006364/1
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Affiliation(s)
- Rosana Alves
- Center of Molecular and Environmental Biology, Department of Biology, University of Minho, Braga, Portugal
| | - Stavroula L. Kastora
- Aberdeen Fungal Group, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen, UK
| | - Alexandra Gomes-Gonçalves
- Center of Molecular and Environmental Biology, Department of Biology, University of Minho, Braga, Portugal
| | - Nuno Azevedo
- LIBRO - Laboratório de Investigação em Biofilmes Rosário Oliveira, Center for Biological Engineering, University of Minho, Braga, Portugal
| | - Célia F. Rodrigues
- LIBRO - Laboratório de Investigação em Biofilmes Rosário Oliveira, Center for Biological Engineering, University of Minho, Braga, Portugal
- LEPABE, Department of Chemical Engineering, University of Porto, Porto, Portugal
| | - Sónia Silva
- LIBRO - Laboratório de Investigação em Biofilmes Rosário Oliveira, Center for Biological Engineering, University of Minho, Braga, Portugal
| | - Liesbeth Demuyser
- VIB-KU Leuven Center for Microbiology, Flanders, Belgium
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Leuven, Belgium
| | - Patrick Van Dijck
- VIB-KU Leuven Center for Microbiology, Flanders, Belgium
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Leuven, Belgium
| | - Margarida Casal
- Center of Molecular and Environmental Biology, Department of Biology, University of Minho, Braga, Portugal
| | - Alistair J. P. Brown
- Aberdeen Fungal Group, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen, UK
- MRC Center for Medical Mycology, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter, UK
| | - Mariana Henriques
- LIBRO - Laboratório de Investigação em Biofilmes Rosário Oliveira, Center for Biological Engineering, University of Minho, Braga, Portugal
| | - Sandra Paiva
- Center of Molecular and Environmental Biology, Department of Biology, University of Minho, Braga, Portugal
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12
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Hernández-Chávez MJ, Clavijo-Giraldo DM, Novák Á, Lozoya-Pérez NE, Martínez-Álvarez JA, Salinas-Marín R, Hernández NV, Martínez-Duncker I, Gácser A, Mora-Montes HM. Role of Protein Mannosylation in the Candida tropicalis-Host Interaction. Front Microbiol 2019; 10:2743. [PMID: 31849889 PMCID: PMC6892782 DOI: 10.3389/fmicb.2019.02743] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 11/11/2019] [Indexed: 12/12/2022] Open
Abstract
Mannans are components of the fungal wall attached to proteins via N- or O-linkages. In Candida albicans, Och1 is an α1,6-mannosyltransferase that adds the first mannose unit to the N-linked mannan outer chain; whereas Pmr1 is an ion pump that imports Mn2+ into the Golgi lumen. This cation is the cofactor of Golgi-resident mannosyltransferases, and thus Pmr1 is involved in the synthesis of both N- and O-linked mannans. Since we currently have limited information about the genetic network behind the Candida tropicalis protein mannosylation machinery, we disrupted OCH1 and PMR1 in this organism. The C. tropicalis pmr1Δ and och1Δ mutants showed increased doubling times, aberrant colony and cellular morphology, reduction in the wall mannan content, and increased susceptibility to wall perturbing agents. These changes were accompanied by increased exposure of both β1,3-glucan and chitin at the wall surface of both mutant strains. Our results showed that O-linked mannans are dispensable for cytokine production by human mononuclear cells, but N-linked mannans and β1,3-glucan are key ligands to trigger cytokine production in a co-stimulatory pathway involving dectin-1 and mannose receptor. Moreover, we found that the N-linked mannan core found on the surface of C. tropicalis och1Δ null mutant was capable of inducing cytokine production; and that a mannan-independent pathway for IL-10 production is present in the C. tropicalis-mononuclear cell interaction. Both mutant strains showed virulence attenuation in the Galleria mellonella and the mouse model of systemic candidiasis. Therefore, mannans are relevant for cell wall composition and organization, and for the C. tropicalis-host interaction.
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Affiliation(s)
- Marco J Hernández-Chávez
- Departamento de Biología, División de Ciencias Naturales y Exactas, Campus Guanajuato, Universidad de Guanajuato, Guanajuato, Mexico
| | - Diana M Clavijo-Giraldo
- Departamento de Biología, División de Ciencias Naturales y Exactas, Campus Guanajuato, Universidad de Guanajuato, Guanajuato, Mexico
| | - Ádám Novák
- Department of Microbiology, University of Szeged, Szeged, Hungary
| | - Nancy E Lozoya-Pérez
- Departamento de Biología, División de Ciencias Naturales y Exactas, Campus Guanajuato, Universidad de Guanajuato, Guanajuato, Mexico
| | - José A Martínez-Álvarez
- Departamento de Biología, División de Ciencias Naturales y Exactas, Campus Guanajuato, Universidad de Guanajuato, Guanajuato, Mexico
| | - Roberta Salinas-Marín
- Laboratorio de Glicobiología Humana y Diagnóstico Molecular, Universidad Autónoma del Estado de Morelos, Cuernavaca, Mexico
| | - Nahúm V Hernández
- Departamento de Biología, División de Ciencias Naturales y Exactas, Campus Guanajuato, Universidad de Guanajuato, Guanajuato, Mexico
| | - Iván Martínez-Duncker
- Laboratorio de Glicobiología Humana y Diagnóstico Molecular, Universidad Autónoma del Estado de Morelos, Cuernavaca, Mexico
| | - Attila Gácser
- Department of Microbiology, University of Szeged, Szeged, Hungary.,MTA-SZTE "Lendület" Mycobiome Research Group, University of Szeged, Szeged, Hungary
| | - Héctor M Mora-Montes
- Departamento de Biología, División de Ciencias Naturales y Exactas, Campus Guanajuato, Universidad de Guanajuato, Guanajuato, Mexico
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13
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Hernández-Chávez MJ, Franco B, Clavijo-Giraldo DM, Hernández NV, Estrada-Mata E, Mora-Montes HM. Role of protein phosphomannosylation in the Candida tropicalis-macrophage interaction. FEMS Yeast Res 2019; 18:4989128. [PMID: 29718196 DOI: 10.1093/femsyr/foy053] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Accepted: 04/26/2018] [Indexed: 12/16/2022] Open
Abstract
Candida tropicalis is an opportunistic fungal pathogen responsible for mucosal and systemic infections. The cell wall is the initial contact point between a fungal cell and the host immune system, and mannoproteins are important components that play key roles when interacting with host cells. In Candida albicans, mannans are modified by mannosyl-phosphate moieties, named phosphomannans, which can work as molecular scaffolds to synthesize β1,2-mannooligosaccharides, and MNN4 is a positive regulator of the phosphomannosylation pathway. Here, we showed that C. tropicalis also displays phosphomannans on the cell surface, but the amount of this cell wall component varies depending on the fungal strain. We also identified a functional ortholog of CaMNN4 in C. tropicalis. Disruption of this gene caused depletion of phosphomannan content. The C. tropicalis mnn4Δ did not show defects in the ability to stimulate cytokine production by human mononuclear cells but displayed virulence attenuation in an insect model of candidiasis. When the mnn4Δ-macrophage interaction was analyzed, results showed that presence of cell wall phosphomannan was critical for C. tropicalis phagocytosis. Finally, our results strongly suggest a differential role for phosphomannans during phagocytosis of C. albicans and C. tropicalis.
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Affiliation(s)
- Marco J Hernández-Chávez
- Departamento de Biología, Universidad de Guanajuato, Noria Alta s/n, col. Noria Alta, C.P. 36050, Guanajuato, Gto., México
| | - Bernardo Franco
- Departamento de Biología, Universidad de Guanajuato, Noria Alta s/n, col. Noria Alta, C.P. 36050, Guanajuato, Gto., México
| | - Diana M Clavijo-Giraldo
- Departamento de Biología, Universidad de Guanajuato, Noria Alta s/n, col. Noria Alta, C.P. 36050, Guanajuato, Gto., México
| | - Nahúm V Hernández
- Departamento de Biología, Universidad de Guanajuato, Noria Alta s/n, col. Noria Alta, C.P. 36050, Guanajuato, Gto., México
| | - Eine Estrada-Mata
- Departamento de Biología, Universidad de Guanajuato, Noria Alta s/n, col. Noria Alta, C.P. 36050, Guanajuato, Gto., México
| | - Héctor Manuel Mora-Montes
- Departamento de Biología, Universidad de Guanajuato, Noria Alta s/n, col. Noria Alta, C.P. 36050, Guanajuato, Gto., México
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14
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Lozoya-Pérez NE, Casas-Flores S, de Almeida JRF, Martínez-Álvarez JA, López-Ramírez LA, Jannuzzi GP, Trujillo-Esquivel E, Estrada-Mata E, Almeida SR, Franco B, Lopes-Bezerra LM, Mora-Montes HM. Silencing of OCH1 unveils the role of Sporothrix schenckii N-linked glycans during the host-fungus interaction. Infect Drug Resist 2018; 12:67-85. [PMID: 30643435 PMCID: PMC6312695 DOI: 10.2147/idr.s185037] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Sporothrix schenckii is a neglected fungal pathogen for the human being and other mammals. In several fungal systems, Och1 is a Golgi α1,6-mannosyltransferase with a key function in the synthesis of N-linked glycans; which are important elements during the host-fungus interplay. The role of OCH1 in fungal virulence seems to be species-specific, being an essential component for Candida albicans virulence and dispensable during the interaction of Aspergillus fumigatus with the host. METHODS Here, we silenced S. schenckii OCH1 and characterized the phenotype of the mutant strains. RESULTS The mutant strains did not show defects in the cell or colony morphology, the growth rate or the ability to undergo dimorphism; but the cell wall changed in both composition and exposure of inner components at the surface. When interacting with human monocytes, the silenced strains had a reduced ability to stimulate TNFα and IL-6 but stimulated higher levels of IL-10. The interaction with human macrophages was also altered, with reduced numbers of silenced cells phagocytosed. These strains showed virulence attenuation in both Galleria mellonella and in the mouse model of sporotrichosis. Nonetheless, the cytokine levels in infected organs did not vary significantly when compared with the wild-type strain. CONCLUSION Our data demonstrate that OCH1 silencing affects different aspects of the S. schenckii-host interaction.
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Affiliation(s)
- Nancy E Lozoya-Pérez
- Department of Biology, Division of Exact and Natural Sciences, Universidad de Guanajuato, Guanajuato, Mexico,
| | | | | | - José A Martínez-Álvarez
- Department of Biology, Division of Exact and Natural Sciences, Universidad de Guanajuato, Guanajuato, Mexico,
| | - Luz A López-Ramírez
- Department of Biology, Division of Exact and Natural Sciences, Universidad de Guanajuato, Guanajuato, Mexico,
| | | | - Elías Trujillo-Esquivel
- Department of Biology, Division of Exact and Natural Sciences, Universidad de Guanajuato, Guanajuato, Mexico,
| | - Eine Estrada-Mata
- Department of Biology, Division of Exact and Natural Sciences, Universidad de Guanajuato, Guanajuato, Mexico,
| | - Sandro R Almeida
- Laboratory of Clinical Mycology, Faculty of Pharmacy, Universidade de São Paulo, São Paulo, Brazil
| | - Bernardo Franco
- Department of Biology, Division of Exact and Natural Sciences, Universidad de Guanajuato, Guanajuato, Mexico,
| | - Leila M Lopes-Bezerra
- Laboratory of Clinical Mycology, Faculty of Pharmacy, Universidade de São Paulo, São Paulo, Brazil
- Laboratory of Cellular Mycology and Proteomics, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Héctor M Mora-Montes
- Department of Biology, Division of Exact and Natural Sciences, Universidad de Guanajuato, Guanajuato, Mexico,
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15
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Targeting Candida spp. to develop antifungal agents. Drug Discov Today 2018; 23:802-814. [PMID: 29353694 DOI: 10.1016/j.drudis.2018.01.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2017] [Revised: 12/09/2017] [Accepted: 01/04/2018] [Indexed: 01/15/2023]
Abstract
Invasive fungal infections are a complex challenge throughout the world because of their high incidence, mainly in critically ill patients, and high mortality rates. The antifungal agents currently available are limited; thus, there is a need for the rapid development of new drugs. In silico methods are a modern strategy to explore interactions between new compounds and specific fungal targets, but they depend on precise genetic information. Here, we discuss the main Candida spp. target genes, including information about null mutants, virulence, cytolocalization, co-regulatory genes, and compounds that are related to protein expression. These data will provide a basis for the future in silico development of antifungal drugs.
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16
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González-Hernández RJ, Jin K, Hernández-Chávez MJ, Díaz-Jiménez DF, Trujillo-Esquivel E, Clavijo-Giraldo DM, Tamez-Castrellón AK, Franco B, Gow NAR, Mora-Montes HM. Phosphomannosylation and the Functional Analysis of the Extended Candida albicans MNN4-Like Gene Family. Front Microbiol 2017; 8:2156. [PMID: 29163439 PMCID: PMC5681524 DOI: 10.3389/fmicb.2017.02156] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2017] [Accepted: 10/20/2017] [Indexed: 11/21/2022] Open
Abstract
Phosphomannosylation is a modification of cell wall proteins that occurs in some species of yeast-like organisms, including the human pathogen Candida albicans. These modified mannans confer a negative charge to the wall, which is important for the interactions with phagocytic cells of the immune systems and cationic antimicrobial peptides. In Saccharomyces cerevisiae, the synthesis of phosphomannan relies on two enzymes, the phosphomannosyltransferase Ktr6 and its positive regulator Mnn4. However, in C. albicans, at least three phosphomannosyltransferases, Mnn4, Mnt3 and Mnt5, participate in the addition of phosphomannan. In addition to MNN4, C. albicans has a MNN4-like gene family composed of seven other homologous members that have no known function. Here, using the classical mini-Ura-blaster approach and the new gene knockout CRISPR-Cas9 system for gene disruption, we generated mutants lacking single and multiple genes of the MNN4 family; and demonstrate that, although Mnn4 has a major impact on the phosphomannan content, MNN42 was also required for full protein phosphomannosylation. The reintroduction of MNN41, MNN42, MNN46, or MNN47 in a genetic background lacking MNN4 partially restored the phenotype associated with the mnn4Δ null mutant, suggesting that there is partial redundancy of function between some family members and that the dominant effect of MNN4 over other genes could be due to its relative abundance within the cell. We observed that additional copies of alleles number of any of the other family members, with the exception of MNN46, restored the phosphomannan content in cells lacking both MNT3 and MNT5. We, therefore, suggest that phosphomannosylation is achieved by three groups of proteins: [i] enzymes solely activated by Mnn4, [ii] enzymes activated by the dual action of Mnn4 and any of the products of other MNN4-like genes, with exception of MNN46, and [iii] activation of Mnt3 and Mnt5 by Mnn4 and Mnn46. Therefore, although the MNN4-like genes have the potential to functionally redundant with Mnn4, they apparently do not play a major role in cell wall mannosylation under most in vitro growth conditions. In addition, our phenotypic analyses indicate that several members of this gene family influence the ability of macrophages to phagocytose C. albicans cells.
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Affiliation(s)
| | - Kai Jin
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
- School of Life Sciences, Chongqing University, Chongqing, China
| | - Marco J. Hernández-Chávez
- División de Ciencias Naturales y Exactas, Departamento de Biología, Universidad de Guanajuato, Guanajuato, Mexico
| | - Diana F. Díaz-Jiménez
- Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Guanajuato, Mexico
| | - Elías Trujillo-Esquivel
- División de Ciencias Naturales y Exactas, Departamento de Biología, Universidad de Guanajuato, Guanajuato, Mexico
| | - Diana M. Clavijo-Giraldo
- División de Ciencias Naturales y Exactas, Departamento de Biología, Universidad de Guanajuato, Guanajuato, Mexico
| | - Alma K. Tamez-Castrellón
- División de Ciencias Naturales y Exactas, Departamento de Biología, Universidad de Guanajuato, Guanajuato, Mexico
| | - Bernardo Franco
- División de Ciencias Naturales y Exactas, Departamento de Biología, Universidad de Guanajuato, Guanajuato, Mexico
| | - Neil A. R. Gow
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Héctor M. Mora-Montes
- División de Ciencias Naturales y Exactas, Departamento de Biología, Universidad de Guanajuato, Guanajuato, Mexico
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17
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Hernández NV, López-Ramírez LA, Díaz-Jiménez DF, Mellado-Mojica E, Martínez-Duncker I, López MG, Mora-Montes HM. Saccharomyces cerevisiae KTR4 , KTR5 and KTR7 encode mannosyltransferases differentially involved in the N - and O -linked glycosylation pathways. Res Microbiol 2017; 168:740-750. [DOI: 10.1016/j.resmic.2017.07.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Revised: 07/21/2017] [Accepted: 07/22/2017] [Indexed: 12/23/2022]
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18
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Jones TH, McClelland EE, McFeeters H, McFeeters RL. Novel Antifungal Activity for the Lectin Scytovirin: Inhibition of Cryptococcus neoformans and Cryptococcus gattii. Front Microbiol 2017; 8:755. [PMID: 28536555 PMCID: PMC5422485 DOI: 10.3389/fmicb.2017.00755] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Accepted: 04/12/2017] [Indexed: 11/13/2022] Open
Abstract
Pathogenic cryptococci are encapsulated yeast that can cause severe meningoencephalitis. Existing therapeutic options are dated and there is a growing need for new alternative antifungal agents for these fungi. Here we report novel inhibition of pathogenic cryptococci by the antimicrobial lectin Scytovirin. Inhibition was most potent against Cryptococcus neoformans var neoformans and C. gattii, with MFC values of 500 nM. Scytovirin binding was localized to the cell wall and shown to affect capsule size and release. No effect was observed on melanization or with cells grown in the presence the cell wall stressor Congo red. Synergy with existing antifungals was indicated, most strongly for amphotericin B. Overall, Scytovirin serves as a much needed new avenue for anticryptococcal development.
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Affiliation(s)
- Tyler H Jones
- Department of Chemistry, University of Alabama in Huntsville, HuntsvilleAL, USA
| | - Erin E McClelland
- Department of Biology, Middle Tennessee State University, MurfreesboroTN, USA
| | - Hana McFeeters
- Department of Chemistry, University of Alabama in Huntsville, HuntsvilleAL, USA
| | - Robert L McFeeters
- Department of Chemistry, University of Alabama in Huntsville, HuntsvilleAL, USA
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19
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The two transmembrane regions of Candida albicans Dfi1 contribute to its biogenesis. Biochem Biophys Res Commun 2017; 488:153-158. [PMID: 28483525 DOI: 10.1016/j.bbrc.2017.04.158] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 04/11/2017] [Indexed: 11/22/2022]
Abstract
The opportunistic pathogen Candida albicans forms invasive filaments that grow into host tissues during disease. The glycosylated, integral plasma membrane protein Dfi1 is important for invasive filamentation in a laboratory model, and for lethality in murine disseminated candidiasis. However, Dfi1 topology and essential domains for Dfi1 biogenesis were undefined. Sequence analysis predicted that Dfi1 contains two transmembrane regions, located near the N- and C-termini. In this communication, we show that Dfi1 remains an integral membrane protein despite deletion of either predicted transmembrane region, whereas deletion of both regions results in a soluble protein. Additionally, Dfi1 that was properly oriented in the membrane, as indicated by N-linked glycosylation, was observed when either transmembrane region was deleted, but was absent when both transmembrane regions were deleted. Interestingly, deletion of the N-terminal transmembrane region resulted in production of two forms of Dfi1. Most of the protein molecules acquired normal N-linked glycosylation and a smaller population failed to become normally N-linked glycosylated. This defect was reversed by replacement of the N-terminal hydrophobic sequence with one synthetic transmembrane sequence but not another. Finally, microscopy studies revealed that Dfi1 lacking the N-terminal transmembrane region was observed at the cell periphery, where full-length Dfi1 normally localizes, whereas the double-truncation mutant was diffusely intracellular. Therefore, mature Dfi1 protein contains two transmembrane domains which contribute to its biogenesis.
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20
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O'Meara TR, Veri AO, Ketela T, Jiang B, Roemer T, Cowen LE. Global analysis of fungal morphology exposes mechanisms of host cell escape. Nat Commun 2015; 6:6741. [PMID: 25824284 PMCID: PMC4382923 DOI: 10.1038/ncomms7741] [Citation(s) in RCA: 177] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 02/24/2015] [Indexed: 11/13/2022] Open
Abstract
Developmental transitions between single-cell yeast and multicellular filaments underpin virulence of diverse fungal pathogens. For the leading human fungal pathogen Candida albicans, filamentation is thought to be required for immune cell escape via induction of an inflammatory programmed cell death. Here we perform a genome-scale analysis of C. albicans morphogenesis and identify 102 negative morphogenetic regulators and 872 positive regulators, highlighting key roles for ergosterol biosynthesis and N-linked glycosylation. We demonstrate that C. albicans filamentation is not required for escape from host immune cells; instead, macrophage pyroptosis is driven by fungal cell-wall remodelling and exposure of glycosylated proteins in response to the macrophage phagosome. The capacity of killed, previously phagocytized cells to drive macrophage lysis is also observed with the distantly related fungal pathogen Cryptococcus neoformans. This study provides a global view of morphogenetic circuitry governing a key virulence trait, and illuminates a new mechanism by which fungi trigger host cell death. Several pathogenic fungi such as Candida albicans undergo transitions between single-celled forms and multicellular filaments. Here the authors perform a genome-scale analysis of C. albicans and show that, contrary to common belief, filamentation is not required for escape from host immune cells.
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Affiliation(s)
- Teresa R O'Meara
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada M5S 1A8
| | - Amanda O Veri
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada M5S 1A8
| | - Troy Ketela
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada M5S 1A8
| | - Bo Jiang
- Bioprocess Technology &Expression, Merck Research Laboratories, 2000 Galloping Hill Rd, Kenilworth, New Jersey 07033, USA
| | - Terry Roemer
- Department of Infectious Diseases, Merck Research Laboratories, 2000 Galloping Hill Rd, Kenilworth, New Jersey 07033, USA
| | - Leah E Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada M5S 1A8
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