Peptide Detection of Fungal Functional Amyloids in Infected Tissue

Garcia-Sherman, Melissa C.; Lysak, Nataliya; Filonenko, Alexandra; Richards, Hazel L.; Sobonya, Richard E.; Klotz, Stephen A.; Lipke, Peter N.

doi:10.1371/journal.pone.0086067

Cited by 24 publications

(23 citation statements)

References 50 publications

(93 reference statements)

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“…In our studies with candidiasis amyloid was detected on hyphae and yeast cells where it forms spontaneously as aggregates of cell surface adhesion molecules. 17,18 The Als adhesins of Candida albicans attach fungi to host tissue and other Candida cells, 19 are demonstrable in infected tissue 4,20 and are antigenic. 21 Such functional amyloids are common in fungal adhesins.…”

Section: Discussionmentioning

confidence: 99%

A unique biofilm in human deep mycoses: fungal amyloid is bound by host serum amyloid P component

Garcia-Sherman

Lundberg

Sobonya

et al. 2015

npj Biofilms Microbiomes

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Background/ObjectivesWe have demonstrated the presence of Candida cell surface amyloids that are important in aggregation of fungi and adherence to tissue. Fungal amyloid was present in invasive human candidal infections and host serum amyloid P component (SAP) bound to the fungal amyloid. SAP is a protease-resistant glycoprotein that binds avidly to amyloid and interferes with host defence, especially against bacterial pathogens for which neutrophils are important. In this study, we investigated whether biofilm of fungal amyloid and SAP was a feature of other disseminated fungal infections.MethodsTissue specimens from 15 autopsies were systematically evaluated with multiple histochemical stains including thioflavin T and Congo red (dyes that stain amyloid), as well as antibody to SAP. We studied specimens with disseminated aspergillosis, mucormycosis and coccidioidomycosis. The structure of the lesions, host inflammatory cells and the presence of fungal amyloid and SAP were determined.ResultsThe structure of the lesions was characteristic in aspergillosis (‘starburst’) and mucormycosis (closely apposed bundles of hyphae). Host inflammatory cells were absent or few in number within these lesions. In Coccidioides lesions, host inflammation was sparse as well. Fungal amyloid was a prominent feature of all lesions along with abundant SAP bound to hyphae and spherules. Fungal amyloid and SAP perhaps contributed to persistence in caseous necrosis lesions. SAP also bound to Aspergillus and Mucorales amyloid in vitro.ConclusionsA biofilm including amyloid and SAP is present in invasive fungal infections. This biofilm may dampen host defence leading to the characteristic sparse inflammatory reaction found in these infections.

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Section: Discussionmentioning

confidence: 99%

A unique biofilm in human deep mycoses: fungal amyloid is bound by host serum amyloid P component

Garcia-Sherman

Lundberg

Sobonya

et al. 2015

npj Biofilms Microbiomes

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“…Als protein surface amyloids are present on C . albicans abscesses in infected tissue, so the nanodomains must form during the infection process, perhaps due to friction exerted by fungal growth through the host tissue [ 30 , 31 ]. Thus, the data strengthens a generally applicable model of force-activated fungal cell adhesion [ 4 , 7 , 24 ].…”

Section: Discussionmentioning

confidence: 99%

Quantitative Analyses of Force-Induced Amyloid Formation in Candida albicans Als5p: Activation by Standard Laboratory Procedures

et al. 2015

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Candida albicans adhesins have amyloid-forming sequences. In Als5p, these amyloid sequences cluster cell surface adhesins to create high avidity surface adhesion nanodomains. Such nanodomains form after force is applied to the cell surface by atomic force microscopy or laminar flow. Here we report centrifuging and resuspending S. cerevisiae cells expressing Als5p led to 1.7-fold increase in initial rate of adhesion to ligand coated beads. Furthermore, mechanical stress from vortex-mixing of Als5p cells or C. albicans cells also induced additional formation of amyloid nanodomains and consequent activation of adhesion. Vortex-mixing for 60 seconds increased the initial rate of adhesion 1.6-fold. The effects of vortex-mixing were replicated in heat-killed cells as well. Activation was accompanied by increases in thioflavin T cell surface fluorescence measured by flow cytometry or by confocal microscopy. There was no adhesion activation in cells expressing amyloid-impaired Als5pV326N or in cells incubated with inhibitory concentrations of anti-amyloid dyes. Together these results demonstrated the activation of cell surface amyloid nanodomains in yeast expressing Als adhesins, and further delineate the forces that can activate adhesion in vivo. Consequently there is quantitative support for the hypothesis that amyloid forming adhesins act as both force sensors and effectors.

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“…In this system, application of force unfolds protein domains to expose amyloid-forming core sequences. As a result, the adhesins aggregate in patches on the cell surface ( 5 , 13 , 23 ), and the presence of the surface patches is associated with a reduced host inflammatory response to fungal infections in Caenorhabditis elegans and in abscesses in human autopsy sections ( 24 – 27 ).…”

Section: Introductionmentioning

confidence: 99%

The Human Disease-Associated Aβ Amyloid Core Sequence Forms Functional Amyloids in a Fungal Adhesin

Rameau

Jackson

Beaussart

et al. 2016

mBio

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There is increasing evidence that many amyloids in living cells have physiological functions. On the surfaces of fungal cells, amyloid core sequences in adhesins can aggregate into 100- to 1,000-nm-wide patches to form high-avidity adhesion nanodomains on the cell surface. The nanodomains form through interactions that have amyloid-like properties: binding of amyloid dyes, perturbation by antiamyloid agents, and interaction with homologous sequences. To test whether these functional interactions are mediated by typical amyloid interactions, we substituted an amyloid core sequence, LVFFA, from human Aβ protein for the native sequence IVIVA in the 1,419-residue Candida albicans adhesin Als5p. The chimeric protein formed cell surface nanodomains and mediated cellular aggregation. The native sequence and chimeric adhesins responded similarly to the amyloid dye thioflavin T and to amyloid perturbants. However, unlike the native protein, the nanodomains formed by the chimeric protein were not force activated and formed less-robust aggregates under flow. These results showed the similarity of amyloid interactions in the amyloid core sequences of native Als5p and Aβ, but they also highlighted emergent properties of the native sequence. Also, a peptide composed of the Aβ amyloid sequence flanked by amino acids from the adhesin formed two-dimensional sheets with sizes similar to the cell surface patches of the adhesins. These results inform an initial model for the structure of fungal cell surface amyloid nanodomains.

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Peptide Detection of Fungal Functional Amyloids in Infected Tissue

Cited by 24 publications

References 50 publications

A unique biofilm in human deep mycoses: fungal amyloid is bound by host serum amyloid P component

A unique biofilm in human deep mycoses: fungal amyloid is bound by host serum amyloid P component

Quantitative Analyses of Force-Induced Amyloid Formation in Candida albicans Als5p: Activation by Standard Laboratory Procedures

The Human Disease-Associated Aβ Amyloid Core Sequence Forms Functional Amyloids in a Fungal Adhesin

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