Defects in intracellular trafficking of fungal cell wall synthases lead to aberrant host immune recognition.

The human fungal pathogen, Cryptococcus neoformans, dramatically alters its cell wall, both in size and composition, upon entering the host. This cell wall remodeling is essential for host immune avoidance by this pathogen. In a genetic screen for mutants with changes in their cell wall, we identifi...

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Main Authors: Shannon K Esher, Kyla S Ost, Maria A Kohlbrenner, Kaila M Pianalto, Calla L Telzrow, Althea Campuzano, Connie B Nichols, Carol Munro, Floyd L Wormley, J Andrew Alspaugh
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2018-06-01
Series:PLoS Pathogens
Online Access:https://storage.googleapis.com/plos-corpus-prod/10.1371/journal.ppat.1007126/2/ppat.1007126.pdf?X-Goog-Algorithm=GOOG4-RSA-SHA256&X-Goog-Credential=wombat-sa%40plos-prod.iam.gserviceaccount.com%2F20210223%2Fauto%2Fstorage%2Fgoog4_request&X-Goog-Date=20210223T042927Z&X-Goog-Expires=3600&X-Goog-SignedHeaders=host&X-Goog-Signature=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author Shannon K Esher
Kyla S Ost
Maria A Kohlbrenner
Kaila M Pianalto
Calla L Telzrow
Althea Campuzano
Connie B Nichols
Carol Munro
Floyd L Wormley
J Andrew Alspaugh
author_facet Shannon K Esher
Kyla S Ost
Maria A Kohlbrenner
Kaila M Pianalto
Calla L Telzrow
Althea Campuzano
Connie B Nichols
Carol Munro
Floyd L Wormley
J Andrew Alspaugh
author_sort Shannon K Esher
collection DOAJ
description The human fungal pathogen, Cryptococcus neoformans, dramatically alters its cell wall, both in size and composition, upon entering the host. This cell wall remodeling is essential for host immune avoidance by this pathogen. In a genetic screen for mutants with changes in their cell wall, we identified a novel protein, Mar1, that controls cell wall organization and immune evasion. Through phenotypic studies of a loss-of-function strain, we have demonstrated that the mar1Δ mutant has an aberrant cell surface and a defect in polysaccharide capsule attachment, resulting in attenuated virulence. Furthermore, the mar1Δ mutant displays increased staining for exposed cell wall chitin and chitosan when the cells are grown in host-like tissue culture conditions. However, HPLC analysis of whole cell walls and RT-PCR analysis of cell wall synthase genes demonstrated that this increased chitin exposure is likely due to decreased levels of glucans and mannans in the outer cell wall layers. We observed that the Mar1 protein differentially localizes to cellular membranes in a condition dependent manner, and we have further shown that the mar1Δ mutant displays defects in intracellular trafficking, resulting in a mislocalization of the β-glucan synthase catalytic subunit, Fks1. These cell surface changes influence the host-pathogen interaction, resulting in increased macrophage activation to microbial challenge in vitro. We established that several host innate immune signaling proteins are required for the observed macrophage activation, including the Card9 and MyD88 adaptor proteins, as well as the Dectin-1 and TLR2 pattern recognition receptors. These studies explore novel mechanisms by which a microbial pathogen regulates its cell surface in response to the host, as well as how dysregulation of this adaptive response leads to defective immune avoidance.
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spelling doaj.art-eeac4427a615407a9b1fdb9e2afb7a602025-02-27T05:31:53ZengPublic Library of Science (PLoS)PLoS Pathogens1553-73661553-73742018-06-01146e100712610.1371/journal.ppat.1007126Defects in intracellular trafficking of fungal cell wall synthases lead to aberrant host immune recognition.Shannon K EsherKyla S OstMaria A KohlbrennerKaila M PianaltoCalla L TelzrowAlthea CampuzanoConnie B NicholsCarol MunroFloyd L WormleyJ Andrew AlspaughThe human fungal pathogen, Cryptococcus neoformans, dramatically alters its cell wall, both in size and composition, upon entering the host. This cell wall remodeling is essential for host immune avoidance by this pathogen. In a genetic screen for mutants with changes in their cell wall, we identified a novel protein, Mar1, that controls cell wall organization and immune evasion. Through phenotypic studies of a loss-of-function strain, we have demonstrated that the mar1Δ mutant has an aberrant cell surface and a defect in polysaccharide capsule attachment, resulting in attenuated virulence. Furthermore, the mar1Δ mutant displays increased staining for exposed cell wall chitin and chitosan when the cells are grown in host-like tissue culture conditions. However, HPLC analysis of whole cell walls and RT-PCR analysis of cell wall synthase genes demonstrated that this increased chitin exposure is likely due to decreased levels of glucans and mannans in the outer cell wall layers. We observed that the Mar1 protein differentially localizes to cellular membranes in a condition dependent manner, and we have further shown that the mar1Δ mutant displays defects in intracellular trafficking, resulting in a mislocalization of the β-glucan synthase catalytic subunit, Fks1. These cell surface changes influence the host-pathogen interaction, resulting in increased macrophage activation to microbial challenge in vitro. We established that several host innate immune signaling proteins are required for the observed macrophage activation, including the Card9 and MyD88 adaptor proteins, as well as the Dectin-1 and TLR2 pattern recognition receptors. These studies explore novel mechanisms by which a microbial pathogen regulates its cell surface in response to the host, as well as how dysregulation of this adaptive response leads to defective immune avoidance.https://storage.googleapis.com/plos-corpus-prod/10.1371/journal.ppat.1007126/2/ppat.1007126.pdf?X-Goog-Algorithm=GOOG4-RSA-SHA256&X-Goog-Credential=wombat-sa%40plos-prod.iam.gserviceaccount.com%2F20210223%2Fauto%2Fstorage%2Fgoog4_request&X-Goog-Date=20210223T042927Z&X-Goog-Expires=3600&X-Goog-SignedHeaders=host&X-Goog-Signature=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
spellingShingle Shannon K Esher
Kyla S Ost
Maria A Kohlbrenner
Kaila M Pianalto
Calla L Telzrow
Althea Campuzano
Connie B Nichols
Carol Munro
Floyd L Wormley
J Andrew Alspaugh
Defects in intracellular trafficking of fungal cell wall synthases lead to aberrant host immune recognition.
PLoS Pathogens
title Defects in intracellular trafficking of fungal cell wall synthases lead to aberrant host immune recognition.
title_full Defects in intracellular trafficking of fungal cell wall synthases lead to aberrant host immune recognition.
title_fullStr Defects in intracellular trafficking of fungal cell wall synthases lead to aberrant host immune recognition.
title_full_unstemmed Defects in intracellular trafficking of fungal cell wall synthases lead to aberrant host immune recognition.
title_short Defects in intracellular trafficking of fungal cell wall synthases lead to aberrant host immune recognition.
title_sort defects in intracellular trafficking of fungal cell wall synthases lead to aberrant host immune recognition
url https://storage.googleapis.com/plos-corpus-prod/10.1371/journal.ppat.1007126/2/ppat.1007126.pdf?X-Goog-Algorithm=GOOG4-RSA-SHA256&X-Goog-Credential=wombat-sa%40plos-prod.iam.gserviceaccount.com%2F20210223%2Fauto%2Fstorage%2Fgoog4_request&X-Goog-Date=20210223T042927Z&X-Goog-Expires=3600&X-Goog-SignedHeaders=host&X-Goog-Signature=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