Assembly and disassembly of Aspergillus fumigatus conidial rodlets

Valsecchi, Isabel; Lai, Joey; Stephen-Victor, Emmanuel; Pillé, Ariane; Beaussart, Audrey; Lo, Victor; Pham, Chi L.L.; Aimanianda, Vishukumar; Kwan, Ann H.; Duchateau, Magalie; Gianetto, Quentin Giai; Matondo, Mariette; Lehoux, Mélanie; Sheppard, Donald C.; Dufrêne, Yves F.; Bayry, Jagadeesh; Guijarro, J. Iñaki; Sunde, Margaret; Latgé, Jean‐Paul

doi:10.1016/j.tcsw.2019.100023

Cited by 31 publications

(44 citation statements)

References 88 publications

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“…This rodlet layer is exclusively composed of hydrophobins encoded by the RODA gene. This protein is characterized by the presence of eight cysteine residues capable of forming four disulfide bridges and organizing the protein crystal in an amyloid configuration that waterproofs the conidial cell wall (471). How the individual proteins aggregate to form a rodlet layer remains unknown.…”

Section: The Cell Wall: a Protective Coat And The Home Of Virulence Dmentioning

confidence: 99%

Aspergillus fumigatus and Aspergillosis in 2019

2019

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SUMMARY Aspergillus fumigatus is a saprotrophic fungus; its primary habitat is the soil. In its ecological niche, the fungus has learned how to adapt and proliferate in hostile environments. This capacity has helped the fungus to resist and survive against human host defenses and, further, to be responsible for one of the most devastating lung infections in terms of morbidity and mortality. In this review, we will provide (i) a description of the biological cycle of A. fumigatus; (ii) a historical perspective of the spectrum of aspergillus disease and the current epidemiological status of these infections; (iii) an analysis of the modes of immune response against Aspergillus in immunocompetent and immunocompromised patients; (iv) an understanding of the pathways responsible for fungal virulence and their host molecular targets, with a specific focus on the cell wall; (v) the current status of the diagnosis of different clinical syndromes; and (vi) an overview of the available antifungal armamentarium and the therapeutic strategies in the clinical context. In addition, the emergence of new concepts, such as nutritional immunity and the integration and rewiring of multiple fungal metabolic activities occurring during lung invasion, has helped us to redefine the opportunistic pathogenesis of A. fumigatus.

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Section: The Cell Wall: a Protective Coat And The Home Of Virulence Dmentioning

confidence: 99%

Aspergillus fumigatus and Aspergillosis in 2019

2019

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“…Three sites, including K50, K55, and K126, were detected with biotinylation marks. All three lysine residues are localized in the relatively hydrophilic α-helical regions of the protein ( 33 ), suggesting that only the surface-exposed lysine residues are likely to be biotinylated.…”

Section: Resultsmentioning

confidence: 99%

Biotinylated Surfome Profiling Identifies Potential Biomarkers for Diagnosis and Therapy of Aspergillus fumigatus Infection

Jia

Krüger

Blango

et al. 2020

mSphere

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Aspergillus fumigatus is one of the most common airborne molds capable of causing mycoses and allergies in humans. During infection, fungal surface proteins mediate the first contact with the human immune system to evade immune responses or to induce hypersensitivity. Several methods have been established for surface proteomics (surfomics). Biotinylation coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS) identification of peptides is a particularly efficient method to identify the surface-exposed regions of proteins that potentially mediate interaction with the host. After biotinylation of surface proteins during spore germination, we detected 231 different biotinylated surface proteins (including several well-known proteins such as RodA, CcpA, and DppV; allergens; and heat shock proteins [HSPs]), as well as some previously undescribed surface proteins. The dynamic change of the surface proteome was illustrated by detection of a relatively high number of proteins exclusively at one developmental stage. Using immunofluorescence microscopy, we confirmed the surface localization of several HSPs of the HSP70 family, which may have moonlighting functions. Collectively, by comparing our data with data representative of previously published A. fumigatus surface proteomes, our study generated a comprehensive data set corresponding to the A. fumigatus surfome and uncovered the surface-exposed regions of many proteins on the surface of conidia or hyphae. These surface-exposed regions are candidates for direct interaction with host cells and may represent antigenic epitopes that either induce protective immune responses or mediate immune evasion. Thus, our data sets provided and compiled here represent reasonable immunotherapy and diagnostic targets for future investigations. IMPORTANCE Aspergillus fumigatus is the most important airborne human-pathogenic mold, capable of causing both life-threatening invasive pulmonary aspergillosis in immunocompromised patients and allergy-inducing infections in individuals with atopic allergy. Despite its obvious medical relevance, timely diagnosis and efficient antifungal treatment of A. fumigatus infection remain major challenges. Proteins on the surface of conidia (asexually produced spores) and mycelium directly mediate host-pathogen interaction and also may serve as targets for diagnosis and immunotherapy. However, the similarity of protein sequences between A. fumigatus and other organisms, sometimes even including the human host, makes selection of targets for immunological-based studies difficult. Here, using surface protein biotinylation coupled with LC-MS/MS analysis, we identified hundreds of A. fumigatus surface proteins with exposed regions, further defining putative targets for possible diagnostic and immunotherapeutic design.

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“…fumigatus strain used in this study was CEA17_Δ akuB KU80 . The RodAp-cysteine residue point-mutant strains and the RODA deletion mutant were generated as described earlier [ 9 , 10 , 11 ]. All the strains were maintained on 2% malt–agar slants at ambient temperature.…”

Section: Methodsmentioning

confidence: 99%

“…Differentiation of DCs was confirmed by the expression of CD1a and the lack of surface expression of CD14 and CD16 [ 20 ]. DCs were stimulated with conidia or cell wall polysaccharides as described earlier [ 1 , 9 , 21 ]. β-(1,3)-Glucan and α-(1,3)-glucan were used at equal absolute concentrations (1 μg); they varied in their chain size, thus ruling out the possibility of using them at equimolar concentrations.…”

Section: Methodsmentioning

confidence: 99%

“…These cysteine residues are involved in the formation of four disulfide linkages that are critical in the structural organization of RodAp. Previously, we showed that the conserved cysteine residue point (ccrp) mutations in the RodA resulted in conidia devoid of a surface rodlet layer [ 9 ]. Indeed, ccrp-mutations of either single or of four cysteine residues that disrupt one or four disulfide linkages, respectively, resulted in mutant conidia with similar cell surface organization.…”

Section: Introductionmentioning

confidence: 99%

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The Role of RodA-Conserved Cysteine Residues in the Aspergillus fumigatus Conidial Surface Organization

Stephen-Victor

Wong

Karnam

et al. 2020

JoF

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Immune inertness of Aspergillus fumigatus conidia is attributed to its surface rodlet-layer made up of RodAp, characterized by eight conserved cysteine residues forming four disulfide bonds. Earlier, we showed that the conserved cysteine residue point (ccrp) mutations result in conidia devoid of the rodlet layer. Here, we extended our study comparing the surface organization and immunoreactivity of conidia carrying ccrp-mutations with the RODA deletion mutant (∆rodA). Western blot analysis using anti-RodAp antibodies indicated the absence of RodAp in the cytoplasm of ccrp-mutant conidia. Immunolabeling revealed differential reactivity to conidial surface glucans, the ccrp-mutant conidia preferentially binding to α-(1,3)-glucan, ∆rodA conidia selectively bound to β-(1,3)-glucan; the parental strain conidia showed negative labeling. However, permeability of ccrp-mutants and ∆rodA was similar to the parental strain conidia. Proteomic analyses of the conidial surface exposed proteins of the ccrp-mutants showed more similarities with the parental strain, but were significantly different from the ∆rodA. Ccrp-mutant conidia were less immunostimulatory compared to ∆rodA conidia. Our data suggest that (i) the conserved cysteine residues are essential for the trafficking of RodAp and the organization of the rodlet layer on the conidial surface, and (ii) targeted point mutation could be an alternative approach to study the role of fungal cell-wall genes in host–fungal interaction.

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Assembly and disassembly of Aspergillus fumigatus conidial rodlets

Cited by 31 publications

References 88 publications

Aspergillus fumigatus and Aspergillosis in 2019

Aspergillus fumigatus and Aspergillosis in 2019

Biotinylated Surfome Profiling Identifies Potential Biomarkers for Diagnosis and Therapy of Aspergillus fumigatus Infection

The Role of RodA-Conserved Cysteine Residues in the Aspergillus fumigatus Conidial Surface Organization

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