The Buoyancy of
            <i>Cryptococcus neoformans</i>
            Is Affected by Capsule Size

Vij, Raghav; Cordero, Radamés J. B.; Casadevall, Arturo

doi:10.1128/msphere.00534-18

Cited by 13 publications

(19 citation statements)

References 58 publications

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“…MS or V8 medium were used for induction of mating and prepared as described previously [38]. DME medium, minimal medium (MM), and RPMI-contaning medium were used for the induction of Cryptococcus capsule formation [39][40][41]. All other media used in this study were prepared as previously described [39].…”

Section: Strains and Growth Conditionsmentioning

confidence: 99%

A Predicted Mannoprotein Cmp1 Regulates Fungal Virulence in Cryptococcus neoformans

Han

Liu

2020

Pathogens

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The capsule of the fungal pathogen Cryptococcus neoformans consists of glucuronoxylomannan (GXM), glucuronoxylomannogalactan (GXMGal), and mannoproteins (MPs). MPs are a kind of glycoproteins with low content but high immunogenicity, which can stimulate the immune protection of the host. However, there is not much information about the role of mannoproteins in virulence of the human fungal pathogen C. neoformans. In this study, we reported the identification and functional analysis of a predicted mannoprotein Cmp1 that regulates fungal virulence in C. neoformans. Gene expression pattern analysis indicates that the CMP1 gene was ubiquitously expressed at all stages of cryptococcal development. Subcellular localization analysis indicated that Cmp1 was localized in the cytoplasm of cryptococcal cells. Disruption or overexpression of CMP1 results in impairing capsule formation in Cryptococcus, but it does not affect the melanin production and sensitivity under various stress conditions, nor does it affect the sexual reproduction process of Cryptococcus. Survival assay showed that the pathogenicity of the cmp1Δ mutant or the CMP1 overexpression strain was significantly attenuated in a murine inhalation model of cryptococcosis. In conclusion, our findings implied that the mannoprotein Cmp1 is required for the virulence of C. neoformans.

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Section: Strains and Growth Conditionsmentioning

confidence: 99%

A Predicted Mannoprotein Cmp1 Regulates Fungal Virulence in Cryptococcus neoformans

Han

Liu

2020

Pathogens

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“…The GalXM consists of an α-(1 → 6)-galactan backbone with galactomannan side chains that are further substituted with variable numbers of xylose and glucuronic acid residues (1). It has recently been characterized that the polysaccharide capsule can function as a flotation device to facilitate transport and dispersion in aqueous fluids (2).…”

Section: Introductionmentioning

confidence: 99%

Immunomodulatory Role of Capsular Polysaccharides Constituents of Cryptococcus neoformans

et al. 2019

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Cryptococcosis is a systemic fungal infection caused by Cryptococcus neoformans . In immunocompetent patients, cryptococcal infection is often confined to the lungs. In immunocompromised individuals, C. neoformans may cause life-threatening illness, either from novel exposure or through reactivation of a previously acquired latent infection. For example, cryptococcal meningitis is a severe clinical disease that can manifest in people that are immunocompromised due to AIDS. The major constituents of the Cryptococcus polysaccharide capsule, glucuronoxylomannan (GXM), and galactoxylomannan (GalXM), also known as glucuronoxylomanogalactan (GXMGal), are considered the primary virulence factors of Cryptococcus . Despite the predominance of GXM in the polysaccharide capsule, GalXM has more robust immunomodulatory effects on host cellular immunity. This review summarizes current knowledge regarding host- Crytococcus neoformans interactions and the role of capsular polysaccharides in host immunomodulation. Future studies will likely facilitate a better understanding of the mechanisms involved in antigenic recognition and host immune response to C. neoformans and lead to the development of new therapeutic pathways for cryptococcal infection.

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“…We recently showed that titanization is triggered by exposure to components of the bacterial cell wall (9), while interactions between bacteria and the capsule have previously been described (63,64). Capsule also contributes to the buoyancy of Cryptococcus cells (65). As such, the importance of redistributing capsular epitopes during titanization should be considered in the context of Cryptococcus cell biology both in the environment and during infection.…”

Section: Discussionmentioning

confidence: 99%

A Glucuronoxylomannan Epitope Exhibits Serotype-Specific Accessibility and Redistributes towards the Capsule Surface during Titanization of the Fungal Pathogen Cryptococcus neoformans

et al. 2019

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Disseminated infections with the fungal species Cryptococcus neoformans or, less frequently, Cryptococcus gattii are an important cause of mortality in immunocompromised individuals. Central to the virulence of both species is an elaborate polysaccharide capsule that consists predominantly of glucuronoxylomannan (GXM). Due to its abundance, GXM is an ideal target for host antibodies, and several monoclonal antibodies (mAbs) have previously been derived using purified GXM or whole capsular preparations as antigens. In addition to their application in the diagnosis of cryptococcosis, anti-GXM mAbs are invaluable tools for studying capsule structure. In this study, we report the production and characterization of a novel anti-GXM mAb, Crp127, that unexpectedly reveals a role for GXM remodeling during the process of fungal titanization. We show that Crp127 recognizes a GXM epitope in an O-acetylation-dependent, but xylosylation-independent, manner. The epitope is differentially expressed by the four main serotypes of Cryptococcus neoformans and C. gattii, is heterogeneously expressed within clonal populations of C. gattii serotype B strains, and is typically confined to the central region of the enlarged capsule. Uniquely, however, this epitope redistributes to the capsular surface in titan cells, a recently characterized morphotype where haploid 5-μm cells convert to highly polyploid cells of >10 μm with distinct but poorly understood capsular characteristics. Titan cells are produced in the host lung and critical for successful infection. Crp127 therefore advances our understanding of cryptococcal morphological change and may hold significant potential as a tool to differentially identify cryptococcal strains and subtypes.

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The Buoyancy of Cryptococcus neoformans Is Affected by Capsule Size

Cited by 13 publications

References 58 publications

A Predicted Mannoprotein Cmp1 Regulates Fungal Virulence in Cryptococcus neoformans

A Predicted Mannoprotein Cmp1 Regulates Fungal Virulence in Cryptococcus neoformans

Immunomodulatory Role of Capsular Polysaccharides Constituents of Cryptococcus neoformans

A Glucuronoxylomannan Epitope Exhibits Serotype-Specific Accessibility and Redistributes towards the Capsule Surface during Titanization of the Fungal Pathogen Cryptococcus neoformans

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