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

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, Jr, J. Andrew Alspaugh

Research output: Contribution to journalArticle

3 Citations (Scopus)
6 Downloads (Pure)

Abstract

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.
Original languageEnglish
Article numbere1007126
Number of pages43
JournalPLoS Pathogens
Volume14
Issue number6
DOIs
Publication statusPublished - 4 Jun 2018

Fingerprint

Cell Wall
Chitin
Macrophage Activation
Myeloid Differentiation Factor 88
Immune Evasion
Host-Pathogen Interactions
Pattern Recognition Receptors
Mannans
Proteins
Cryptococcus neoformans
Glucans
Chitosan
Capsules
Polysaccharides
Virulence
Catalytic Domain
High Pressure Liquid Chromatography
Staining and Labeling
Polymerase Chain Reaction
Membranes

Cite this

Esher, S. K., Ost, K. S., Kohlbrenner, M. A., Pianalto, K. M., Telzrow, C. L., Campuzano, A., ... Alspaugh, J. A. (2018). Defects in intracellular trafficking of fungal cell wall synthases lead to aberrant host immune recognition. PLoS Pathogens, 14(6), [e1007126]. https://doi.org/10.1371/journal.ppat.1007126

Defects in intracellular trafficking of fungal cell wall synthases lead to aberrant host immune recognition. / Esher, Shannon K. ; Ost, Kyla S.; Kohlbrenner, Maria A.; Pianalto, Kaila M.; Telzrow, Calla L.; Campuzano, Althea; Nichols, Connie B.; Munro, Carol; Wormley, Jr, Floyd L. ; Alspaugh, J. Andrew .

In: PLoS Pathogens, Vol. 14, No. 6, e1007126, 04.06.2018.

Research output: Contribution to journalArticle

Esher, SK, Ost, KS, Kohlbrenner, MA, Pianalto, KM, Telzrow, CL, Campuzano, A, Nichols, CB, Munro, C, Wormley, Jr, FL & Alspaugh, JA 2018, 'Defects in intracellular trafficking of fungal cell wall synthases lead to aberrant host immune recognition', PLoS Pathogens, vol. 14, no. 6, e1007126. https://doi.org/10.1371/journal.ppat.1007126
Esher SK, Ost KS, Kohlbrenner MA, Pianalto KM, Telzrow CL, Campuzano A et al. Defects in intracellular trafficking of fungal cell wall synthases lead to aberrant host immune recognition. PLoS Pathogens. 2018 Jun 4;14(6). e1007126. https://doi.org/10.1371/journal.ppat.1007126
Esher, Shannon K. ; Ost, Kyla S. ; Kohlbrenner, Maria A. ; Pianalto, Kaila M. ; Telzrow, Calla L. ; Campuzano, Althea ; Nichols, Connie B. ; Munro, Carol ; Wormley, Jr, Floyd L. ; Alspaugh, J. Andrew . / Defects in intracellular trafficking of fungal cell wall synthases lead to aberrant host immune recognition. In: PLoS Pathogens. 2018 ; Vol. 14, No. 6.
@article{de134effd9334ebd97e83241af6afe58,
title = "Defects in intracellular trafficking of fungal cell wall synthases lead to aberrant host immune recognition",
abstract = "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.",
author = "Esher, {Shannon K.} and Ost, {Kyla S.} and Kohlbrenner, {Maria A.} and Pianalto, {Kaila M.} and Telzrow, {Calla L.} and Althea Campuzano and Nichols, {Connie B.} and Carol Munro and {Wormley, Jr}, {Floyd L.} and Alspaugh, {J. Andrew}",
note = "Acknowledgments We acknowledge Jeanette Wagener and Louise Walker for performing the HPAEC-PAD analysis and Neil Gow for providing access to the Dionex HPAEC-PAD instrumentation. We thank Mike Cook and the Duke University Cancer Center Flow Cytometry Shared Resource for assistance with the flow cytometry. We also acknowledge Michelle Plue and the Duke University Shared Materials Institute Facility for performing the transmission electron microscopy. We thank Marcel Wu¨thrich for providing the MyD88-/-and TLR2/4-/- mice, and Mari Shinohara and Elizabeth Deerhake for providing the Dectin-1-/- mice.",
year = "2018",
month = "6",
day = "4",
doi = "10.1371/journal.ppat.1007126",
language = "English",
volume = "14",
journal = "PLoS Pathogens",
issn = "1553-7366",
publisher = "Public Library of Science",
number = "6",

}

TY - JOUR

T1 - Defects in intracellular trafficking of fungal cell wall synthases lead to aberrant host immune recognition

AU - Esher, Shannon K.

AU - Ost, Kyla S.

AU - Kohlbrenner, Maria A.

AU - Pianalto, Kaila M.

AU - Telzrow, Calla L.

AU - Campuzano, Althea

AU - Nichols, Connie B.

AU - Munro, Carol

AU - Wormley, Jr, Floyd L.

AU - Alspaugh, J. Andrew

N1 - Acknowledgments We acknowledge Jeanette Wagener and Louise Walker for performing the HPAEC-PAD analysis and Neil Gow for providing access to the Dionex HPAEC-PAD instrumentation. We thank Mike Cook and the Duke University Cancer Center Flow Cytometry Shared Resource for assistance with the flow cytometry. We also acknowledge Michelle Plue and the Duke University Shared Materials Institute Facility for performing the transmission electron microscopy. We thank Marcel Wu¨thrich for providing the MyD88-/-and TLR2/4-/- mice, and Mari Shinohara and Elizabeth Deerhake for providing the Dectin-1-/- mice.

PY - 2018/6/4

Y1 - 2018/6/4

N2 - 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.

AB - 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.

U2 - 10.1371/journal.ppat.1007126

DO - 10.1371/journal.ppat.1007126

M3 - Article

VL - 14

JO - PLoS Pathogens

JF - PLoS Pathogens

SN - 1553-7366

IS - 6

M1 - e1007126

ER -