Role for chitin and chitooligomers in the capsular architecture of cryptococcus neoformans∇

Fernanda L. Fonseca, Leonardo Nimrichter, Radames J.B. Cordero, Susana Frases, Jessica Rodrigues, David L. Goldman, Ryszard Andruszkiewicz, Slawomir Milewski, Luiz R. Travassos, Arturo Casadevall, Mareio L. Rodrigues

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33 Scopus citations

Abstract

Molecules composed of β-1,4-linked N-acetylglucosamine (GlcNAc) and deacetylated glucosamine units play key roles as surface constituents of the human pathogenic fungus Cryptococcus neoformans. GIcNAc is the monomeric unit of chitin and chitooligomers, which participate in the connection of capsular polysaccharides to the cryptococcal cell wall. In the present study, we evaluated the role of GlcNAc-containing structures in the assembly of the cryptococcal capsule. The in vivo expression of chitooligomers in C. neoformans varied depending on the infected tissue, as inferred from the differential reactivity of yeast forms to the wheat germ agglutinin (WGA) in infected brain and lungs of rats. Chromatographic and dynamic light-scattering analyses demonstrated that glucuronoxylomannan (GXM), the major cryptococcal capsular component, interacts with chitin and chitooligomers. When added to C. neoformans cultures, chitooligomers formed soluble complexes with GXM and interfered in capsular assembly, as manifested by aberrant capsules with defective connections with the cell wall and no reactivity with a monoclonal antibody to GXM. Cultivation of C. neoformans in the presence of an inhibitor of glucosamine 6-phosphate synthase resulted in altered expression of cell wall chitin. These cells formed capsules that were loosely connected to the cryptococcal wall and contained fibers with decreased diameters and altered monosaccharide composition. These results contribute to our understanding of the role played by chitin and chitooligosaccharides on the cryptococcal capsular structure, broadening the functional activities attributed to GlcNAc-containing structures in this biological system.

Original languageEnglish (US)
Pages (from-to)1543-1553
Number of pages11
JournalEukaryotic Cell
Volume8
Issue number10
DOIs
Publication statusPublished - Oct 1 2009
Externally publishedYes

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ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology

Cite this

Fonseca, F. L., Nimrichter, L., Cordero, R. J. B., Frases, S., Rodrigues, J., Goldman, D. L., ... Rodrigues, M. L. (2009). Role for chitin and chitooligomers in the capsular architecture of cryptococcus neoformans∇. Eukaryotic Cell, 8(10), 1543-1553. https://doi.org/10.1128/EC.00142-09