Immunoproteomics based identification of thioredoxin reductase GliT and novel Aspergillus fumigatus antigens for serologic diagnosis of invasive aspergillosis

Shi, Lingen; Li, Fang-qiu; Huang, Mei‐Rong; Lu, Jingfen; Kong, Xiao-xiang; Wang, Shiqin; Shao, Haifeng

doi:10.1186/1471-2180-12-11

Cited by 35 publications

(49 citation statements)

References 44 publications

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“…However, our analysis also identified new immunogenic proteins, including Scw4, Crf2 (25), Pst1, Shm2, GliT, and TpiA, which have not been described as human T cell targets. The gliotoxin oxidase GliT was recently identified via an immunoproteome screening approach and was suggested to represent a novel Ag for serologic diagnosis of aspergillosis (46). Interestingly, two other "immunogenic" proteins, the enolase Aspf22 and Shm2, were detected in immunoblots using sera from patients with allergic bronchopulmonary aspergillosis (50).…”

Section: Discussionmentioning

confidence: 99%

“…So far, CD4 + target proteins primarily have been identified indirectly via the presence of isotype-switched Abs (25,(42)(43)(44)(45)(46)(47). Alternatively, functional T cell assays, such as proliferation or cytokine production, have been used in a few studies (31-33, 38, 39, 48, 49) but do not allow for quantitative enumeration and phenotypic characterization of the reactive T cells.…”

Section: Discussionmentioning

confidence: 99%

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Identification of Immunogenic Antigens from Aspergillus fumigatus by Direct Multiparameter Characterization of Specific Conventional and Regulatory CD4+ T Cells

Bächer

Kniemeyer

Teutschbein

et al. 2014

The Journal of Immunology

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CD4+ T cells orchestrate immune responses against fungi, such as Aspergillus fumigatus, a major fungal pathogen in humans. The complexity of the fungal genome and lifestyle questions the existence of one or a few immune-dominant Ags and complicates systematic screening for immunogenic Ags useful for immunotherapy or diagnostics. In this study, we used a recently developed flow cytometric assay for the direct ex vivo characterization of A. fumigatus–specific CD4+ T cells for rapid identification of physiological T cell targets in healthy donors. We show that the T cell response is primarily directed against metabolically active A. fumigatus morphotypes and is stronger against membrane protein fractions compared with cell wall or cytosolic proteins. Further analysis of 15 selected single A. fumigatus proteins revealed a highly diverse reactivity pattern that was donor and protein dependent. Importantly, the parallel assessment of T cell frequency, phenotype, and function allowed us to differentiate between proteins that elicit strong memory T cell responses in vivo versus Ags that induce T cell exhaustion or no reactivity in vivo. The regulatory T cell (Treg) response mirrors the conventional T cell response in terms of numbers and target specificity. Thus, our data reveal that the fungal T cell immunome is complex, but the ex vivo characterization of reactive T cells allows us to classify Ags and to predict potential immunogenic targets. A. fumigatus–specific conventional T cell responses are counterbalanced by a strong Treg response, suggesting that Treg-depletion strategies may be helpful in improving antifungal immunity.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Identification of Immunogenic Antigens from Aspergillus fumigatus by Direct Multiparameter Characterization of Specific Conventional and Regulatory CD4+ T Cells

Bächer

Kniemeyer

Teutschbein

et al. 2014

The Journal of Immunology

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“…A. fumigatus exposure can also induce debilitating aspergillosis and allergy in immunocompetent individuals [2,3]. Selected secondary metabolites produced by A. fumigatus, in particular siderophores and the non-ribosomal peptide gliotoxin, are generally considered to be front-line virulence factors [4,5].…”

Section: Contextualizing and Rethinking Gliotoxinmentioning

confidence: 99%

Resistance is not futile: gliotoxin biosynthesis, functionality and utility

Dolan¹,

O’Keeffe²,

Jones

et al. 2015

Trends in Microbiology

102

146

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Gliotoxin biosynthesis is encoded by the gli gene cluster in Aspergillus fumigatus. The biosynthesis of gliotoxin is influenced by a suite of transcriptionally-active regulatory proteins and a bis-thiomethyltransferase. A selfprotection system against gliotoxin is present in A. fumigatus. Several additional metabolites are also produced via the gliotoxin biosynthetic pathway. Moreover, the biosynthesis of unrelated natural products appears to be influenced either by gliotoxin or by the activity of specific reactions within the biosynthetic pathway. The activity of gliotoxin against animal cells and fungi, often mediated by interference with redox homeostasis or protein modification, is revealing new metabolic interactions within eukaryotic systems. Nature has provided a most useful natural product with which to reveal some of its many molecular secrets. Contextualizing and rethinking gliotoxinAspergillus fumigatus is an opportunistic fungal pathogen and primarily infects immunocompromised individuals where it can cause fatal invasive aspergillosis (IA) [1]. A. fumigatus exposure can also induce debilitating aspergillosis and allergy in immunocompetent individuals [2,3]. Selected secondary metabolites produced by A. fumigatus, in particular siderophores and the non-ribosomal peptide gliotoxin, are generally considered to be front-line virulence factors [4,5]. Gliotoxin is an epipolythiodioxopiperazine (ETP) of molecular mass 326 Da, and contains a disulfide bridge which can undergo repeating cleavage and reformation, thereby resulting in a potent intracellular redox activity (Figure 1) [6]. Indeed, the dithiol form of gliotoxin has also been posited to be responsible for the observed biological activities of gliotoxin [7]. Bisdethiobis(methylthio)gliotoxin (BmGT) and related gliotoxin metabolites (Figure 1) are also biosynthesized by A. fumigatus [8,9]. Incredibly, the gliotoxin biosynthetic pathway had remained elusive since the discovery of gliotoxin in 1936; however, recent studies have not only dissected this unusual molecular assembly system but have revealed the necessity for gliotoxin-producing fungi to possess an endogenous resistance system against gliotoxin [10,11]. Moreover, because gliotoxin can be considered as the prototype ETP, studies on gliotoxin can be instrumental in revealing the biosynthetic mechanisms of related ETPs which are biosynthesized by a range of fungi [12]. Amongst others, these include sirodesmin A, sporidesmin A, chaetocin, aranotin, and chetomin [13]. Studies on the biosynthetic mechanism of ETPs, particularly gliotoxin, are also serving to inspire new synthetic chemistry approaches for ETP synthesis and desulfurization, which are somewhat beyond the scope of the present review [13,14].In addition to studying how gliotoxin contributes to organismal virulence, it has also been deployed to explore and reveal novel biochemistry within both fungal and animal cells [15,16]. Thus, we contend that it is the ability of gliotoxin to interfere with so many cellular processes that makes it...

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“…Interestingly, vip1 was found to be an antigen of sera from confirmed IA patients (54), and might provide an opportunity for clinical detection.…”

Section: Fig 5 Go Slim Terms Represented In 24 H and 48 H 10% Hs Cumentioning

confidence: 99%

“…Additionally, the putative P450 fatty acid hydroxylase (Cyp505A13), predicted to catalyze the oxidation of fatty acids during fatty acid metabolism (26), and the ⌬9-stearic acid desaturase (AFUA_7G05920, SdeA), which catalyzes the oxidation of a fatty acid into an unsaturated fatty acid in A. nidulans (62), were measured. Af had HS induced ABP-reactivity of two ergosterol biosynthesis proteins: (1) farnesyl-diphosphate farnesyltransferase (AFUA_7G01220, Erg9) an IA serum antigen, which catalyzes the coupling of two farnesyl pyrophosphate units into squalene at the start of the biosynthetic pathway (54,63), and (2) the azole drug target Cyp51a (Erg11) (64). Most notably Fksp, a single copy essential gene involved in cell wall synthesis had higher reactivity in Af HS culture (65), and the Nf and Ac orthologs were not observed.…”

Section: Fig 5 Go Slim Terms Represented In 24 H and 48 H 10% Hs Cumentioning

confidence: 99%

Disparate Proteome Responses of Pathogenic and Nonpathogenic Aspergilli to Human Serum Measured by Activity-Based Protein Profiling (ABPP)

Wiedner

Ansong

Webb-Robertson

et al. 2013

Molecular & Cellular Proteomics

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Aspergillus fumigatus is the primary pathogen causing the devastating pulmonary disease Invasive Aspergillosis in immunocompromised individuals. There is high genomic synteny between A. fumigatus and closely related rarely pathogenic Neosartorya fischeri and Aspergillus clavatus genomes. We applied activity-based protein profiling to compare unique or overexpressed activitybased probe-reactive proteins of all three fungi over time in minimal media growth and in response to human serum. We found 360 probe-reactive proteins exclusive to A. fumigatus, including known virulence associated proteins, and 13 proteins associated with stress response exclusive to A. fumigatus culture in serum. Though the fungi are highly orthologous, A. fumigatus has a significantly greater number of ABP-reactive proteins across varied biological process. Only 50% of expected orthologs of measured A. fumigatus reactive proteins were observed in N. fischeri and A. clavatus. Activity-based protein profiling identified a number of processes that were induced by human serum in A. fumigatus relative to N. fischeri and A. clavatus. These included actin organization and assembly, transport, and fatty acid, cell membrane, and cell wall synthesis. Additionally, signaling proteins regulating vegetative growth, conidiation, and cell wall integrity, required for appropriate cellular response to external stimuli, had higher activity-based probe-protein reaction over time in A. fumigatus and N. fisheri, but not in A. clavatus. Together, we show that measured proteins and physiological processes identified solely or significantly over-represented in A. fumigatus reveal a unique adaptive response to human protein not found in closely related, but rarely pathogenic aspergilli. These unique activity-based probe-protein responses to culture condition may reveal how A. fumigatus initiates pulmonary invasion leading to Invasive Aspergillosis. Invasive aspergillosis (IA) 1 is a devastating infection caused by the ubiquitous saprophytic filamentous fungus Aspergillus fumigatus (Af) (1). Af is an opportunistic pathogen with no true virulence factors. Its pathogenicity is often attributed to its thermotolerance, response to oxidative stress, ability to grow in hypoxic or iron limiting environments, and its ability to use a variety of carbon and nitrogen sources as nutrients, such as proteins derived from the human host (2). A thorough understanding of biological processes or factors that facilitate pathogenic Af infection compared with other microbial infections is needed to assist treatment and diagnosis of IA.Af protein activity regulation and function, attenuated by environmental response and adaptation, is critical for opportunistic infection and development of IA (3). Activity-based protein profiling (ABPP), coupled to mass spectrometry (MS), is a powerful chemical biology approach for directly identifying a subset of proteins (4). ABPP employs activity-based probes (ABPs) to covalently label and enrich functional families of proteins, thereby reducing th...

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Immunoproteomics based identification of thioredoxin reductase GliT and novel Aspergillus fumigatus antigens for serologic diagnosis of invasive aspergillosis

Cited by 35 publications

References 44 publications

Identification of Immunogenic Antigens from Aspergillus fumigatus by Direct Multiparameter Characterization of Specific Conventional and Regulatory CD4+ T Cells

Identification of Immunogenic Antigens from Aspergillus fumigatus by Direct Multiparameter Characterization of Specific Conventional and Regulatory CD4+ T Cells

Resistance is not futile: gliotoxin biosynthesis, functionality and utility

Disparate Proteome Responses of Pathogenic and Nonpathogenic Aspergilli to Human Serum Measured by Activity-Based Protein Profiling (ABPP)

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