Cargando…

1725. Shear Forces Induce a Transient, Calcineurin-Dependent Hyper-Virulent Phenotype in Mucorales via Soluble Factors

BACKGROUND: Myocutaneous mucormycosis is encountered in settings of extreme mechanical forces such as combat-related blast injuries or natural catastrophes. It is unclear whether the virulence of Mucorales is affected by mechano-biological factors such as shear forces (SF). METHODS: Spores of clinic...

Descripción completa

Detalles Bibliográficos
Autores principales: Wurster, Sebastian, Tatara, Alexander M, Albert, Nathaniel D, Mikos, Antonios G, Ibrahim, Ashraf S, Bruno, Vincent M, Kontoyiannis, Dimitrios P
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Oxford University Press 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6809355/
http://dx.doi.org/10.1093/ofid/ofz360.1588
_version_ 1783461967331065856
author Wurster, Sebastian
Tatara, Alexander M
Albert, Nathaniel D
Mikos, Antonios G
Ibrahim, Ashraf S
Bruno, Vincent M
Kontoyiannis, Dimitrios P
author_facet Wurster, Sebastian
Tatara, Alexander M
Albert, Nathaniel D
Mikos, Antonios G
Ibrahim, Ashraf S
Bruno, Vincent M
Kontoyiannis, Dimitrios P
author_sort Wurster, Sebastian
collection PubMed
description BACKGROUND: Myocutaneous mucormycosis is encountered in settings of extreme mechanical forces such as combat-related blast injuries or natural catastrophes. It is unclear whether the virulence of Mucorales is affected by mechano-biological factors such as shear forces (SF). METHODS: Spores of clinical strains of Rhizopus arrhizus, Rhizomucor pusillus, and Mucor circinelloides (10(7)/mL in PBS) were either kept in static culture (control) or exposed to shear forces (SF) by magnetic stirring for 30 minutes. Mycelial expansion was monitored in the IncuCyte time-lapse microscopy system. For in vivo studies, the dorsal thorax of wild-type Drosophila melanogaster flies (n = 66–76 per condition) was pricked with a needle dipped in control or SF-exposed spore solutions. Flies were also infected with non-exposed spores suspended in cell-free supernatant taken from SF-exposed spores. Survival was monitored for 7 days post-infection. RESULTS: Growth rates and morphogenesis of all isolates were not altered by SF. However, SF-exposed spores of all tested Mucorales isolates exhibited increased pathogenicity in the fly model (7-day survival: SF 8–14%, control 36–44%, P < 0.001). Introducing different resting periods after SF resulted in gradual attenuation of the hyper-virulent phenotype, with survival rates of infected flies returning to the level seen with non-SF-exposed spores after 120 min post-SF resting (Panel A). To gain a mechanistic insight, we added cyclosporine A (CsA, 100 µg/mL) during shear challenge. Compared with SF-exposed spores, CsA addition improved 7-day survival of R. arrhizus-infected flies from 1% to 29% (P < 0.001), whereas the pathogenicity of non-SF-exposed spores was not influenced by CsA. Interestingly, supernatants from SF-exposed R. arrhizus rendered non-exposed spores hyper-virulent (Panel B, P = 0.003). CONCLUSION: SF induces a transient hypervirulent phenotype of Mucorales. Our findings suggest that soluble mediators contribute to increased pathogenicity. Largely attenuated hyper-virulence in the presence of CsA corroborated the previously described relevance of the calcineurin pathway in fungal mechano-biology. RNA sequencing studies are in progress to identify epigenetic alterations in Mucorales following SF. [Image: see text] DISCLOSURES: All authors: No reported disclosures.
format Online
Article
Text
id pubmed-6809355
institution National Center for Biotechnology Information
language English
publishDate 2019
publisher Oxford University Press
record_format MEDLINE/PubMed
spelling pubmed-68093552019-10-28 1725. Shear Forces Induce a Transient, Calcineurin-Dependent Hyper-Virulent Phenotype in Mucorales via Soluble Factors Wurster, Sebastian Tatara, Alexander M Albert, Nathaniel D Mikos, Antonios G Ibrahim, Ashraf S Bruno, Vincent M Kontoyiannis, Dimitrios P Open Forum Infect Dis Abstracts BACKGROUND: Myocutaneous mucormycosis is encountered in settings of extreme mechanical forces such as combat-related blast injuries or natural catastrophes. It is unclear whether the virulence of Mucorales is affected by mechano-biological factors such as shear forces (SF). METHODS: Spores of clinical strains of Rhizopus arrhizus, Rhizomucor pusillus, and Mucor circinelloides (10(7)/mL in PBS) were either kept in static culture (control) or exposed to shear forces (SF) by magnetic stirring for 30 minutes. Mycelial expansion was monitored in the IncuCyte time-lapse microscopy system. For in vivo studies, the dorsal thorax of wild-type Drosophila melanogaster flies (n = 66–76 per condition) was pricked with a needle dipped in control or SF-exposed spore solutions. Flies were also infected with non-exposed spores suspended in cell-free supernatant taken from SF-exposed spores. Survival was monitored for 7 days post-infection. RESULTS: Growth rates and morphogenesis of all isolates were not altered by SF. However, SF-exposed spores of all tested Mucorales isolates exhibited increased pathogenicity in the fly model (7-day survival: SF 8–14%, control 36–44%, P < 0.001). Introducing different resting periods after SF resulted in gradual attenuation of the hyper-virulent phenotype, with survival rates of infected flies returning to the level seen with non-SF-exposed spores after 120 min post-SF resting (Panel A). To gain a mechanistic insight, we added cyclosporine A (CsA, 100 µg/mL) during shear challenge. Compared with SF-exposed spores, CsA addition improved 7-day survival of R. arrhizus-infected flies from 1% to 29% (P < 0.001), whereas the pathogenicity of non-SF-exposed spores was not influenced by CsA. Interestingly, supernatants from SF-exposed R. arrhizus rendered non-exposed spores hyper-virulent (Panel B, P = 0.003). CONCLUSION: SF induces a transient hypervirulent phenotype of Mucorales. Our findings suggest that soluble mediators contribute to increased pathogenicity. Largely attenuated hyper-virulence in the presence of CsA corroborated the previously described relevance of the calcineurin pathway in fungal mechano-biology. RNA sequencing studies are in progress to identify epigenetic alterations in Mucorales following SF. [Image: see text] DISCLOSURES: All authors: No reported disclosures. Oxford University Press 2019-10-23 /pmc/articles/PMC6809355/ http://dx.doi.org/10.1093/ofid/ofz360.1588 Text en © The Author(s) 2019. Published by Oxford University Press on behalf of Infectious Diseases Society of America. http://creativecommons.org/licenses/by-nc-nd/4.0/ This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs licence (http://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial reproduction and distribution of the work, in any medium, provided the original work is not altered or transformed in any way, and that the work is properly cited. For commercial re-use, please contact journals.permissions@oup.com
spellingShingle Abstracts
Wurster, Sebastian
Tatara, Alexander M
Albert, Nathaniel D
Mikos, Antonios G
Ibrahim, Ashraf S
Bruno, Vincent M
Kontoyiannis, Dimitrios P
1725. Shear Forces Induce a Transient, Calcineurin-Dependent Hyper-Virulent Phenotype in Mucorales via Soluble Factors
title 1725. Shear Forces Induce a Transient, Calcineurin-Dependent Hyper-Virulent Phenotype in Mucorales via Soluble Factors
title_full 1725. Shear Forces Induce a Transient, Calcineurin-Dependent Hyper-Virulent Phenotype in Mucorales via Soluble Factors
title_fullStr 1725. Shear Forces Induce a Transient, Calcineurin-Dependent Hyper-Virulent Phenotype in Mucorales via Soluble Factors
title_full_unstemmed 1725. Shear Forces Induce a Transient, Calcineurin-Dependent Hyper-Virulent Phenotype in Mucorales via Soluble Factors
title_short 1725. Shear Forces Induce a Transient, Calcineurin-Dependent Hyper-Virulent Phenotype in Mucorales via Soluble Factors
title_sort 1725. shear forces induce a transient, calcineurin-dependent hyper-virulent phenotype in mucorales via soluble factors
topic Abstracts
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6809355/
http://dx.doi.org/10.1093/ofid/ofz360.1588
work_keys_str_mv AT wurstersebastian 1725shearforcesinduceatransientcalcineurindependenthypervirulentphenotypeinmucoralesviasolublefactors
AT tataraalexanderm 1725shearforcesinduceatransientcalcineurindependenthypervirulentphenotypeinmucoralesviasolublefactors
AT albertnathanield 1725shearforcesinduceatransientcalcineurindependenthypervirulentphenotypeinmucoralesviasolublefactors
AT mikosantoniosg 1725shearforcesinduceatransientcalcineurindependenthypervirulentphenotypeinmucoralesviasolublefactors
AT ibrahimashrafs 1725shearforcesinduceatransientcalcineurindependenthypervirulentphenotypeinmucoralesviasolublefactors
AT brunovincentm 1725shearforcesinduceatransientcalcineurindependenthypervirulentphenotypeinmucoralesviasolublefactors
AT kontoyiannisdimitriosp 1725shearforcesinduceatransientcalcineurindependenthypervirulentphenotypeinmucoralesviasolublefactors