TY - JOUR
T1 - Solid-state NMR spectroscopy identifies three classes of lipids in Cryptococcus neoformans melanized cell walls and whole fungal cells
AU - Chrissian, Christine
AU - Camacho, Emma
AU - Kelly, John E.
AU - Wang, Hsin
AU - Casadevall, Arturo
AU - Stark, Ruth E.
N1 - Funding Information:
We thank Ankur Jadhav (Chemical Engineering, City College of New York) for expert instruction and ongoing support in the use of the software DMfit. We also thank Van Chanh Phan (Hostos Community College, CUNY) for the development of ssNMR programs and technical support with experimental setup. This work was supported by National Institutes of Health Grant R01-AI052733. The 600-MHz NMR facilities used in this work are operated by City College (CCNY) and the CUNY Institute for Macromolecular Assemblies. C. C. was the recipient of fellowships from the United States Department of Education Graduate Assistance in Areas of National Need (GAANN) Program in Biochemistry, Biophysics, and Bio-design at the City College of New York (PA200A120211 and PA200A150068) and the James Whittam research excellence award of the CCNY Department of Chemistry and Biochemistry. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
Funding Information:
Funding and additional information—This work was supported by National Institutes of Health Grant R01-AI052733. The 600-MHz NMR facilities used in this work are operated by City College (CCNY) and the CUNY Institute for Macromolecular Assemblies. C. C. was the recipient of fellowships from the United States Department of Education Graduate Assistance in Areas of National Need (GAANN) Program in Biochemistry, Biophysics, and Bio-design at the City College of New York (PA200A120211 and PA200A150068) and the James Whittam research excellence award of the CCNY Department of Chemistry and Biochemistry. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
Publisher Copyright:
© 2020 Chrissian et al. Published under exclusive license by The American Society for Biochemistry and Molecular Biology, Inc.
PY - 2020/10/30
Y1 - 2020/10/30
N2 - A primary virulence-associated trait of the opportunistic fungal pathogen Cryptococcus neoformans is the production of melanin pigments that are deposited into the cell wall and interfere with the host immune response. Previously, our solid-state NMR studies of isolated melanized cell walls (melanin “ghosts”) revealed that the pigments are strongly associated with lipids, but their identities, origins, and potential roles were undetermined. Herein, we exploited spectral editing techniques to identify and quantify the lipid molecules associated with pigments in melanin ghosts. The lipid profiles were remarkably similar in whole C. neoformans cells, grown under either melanizing or nonmelanizing conditions; triglycerides (TGs), sterol esters (SEs), and polyisoprenoids (PPs) were the major constituents. Although no quantitative differences were found between melanized and nonmelanized cells, melanin ghosts were relatively enriched in SEs and PPs. In contrast to lipid structures reported during early stages of fungal growth in nutrient-rich media, variants found herein could be linked to nutrient stress, cell aging, and subsequent production of substances that promote chronic fungal infections. The fact that TGs and SEs are the typical cargo of lipid droplets suggests that these organelles could be connected to C. neoformans melanin synthesis. Moreover, the discovery of PPs is intriguing because dolichol is a well-established constituent of human neuromelanin. The presence of these lipid species even in nonmelanized cells suggests that they could be produced constitutively under stress conditions in anticipation of melanin synthesis. These findings demonstrate that C. neoformans lipids are more varied compositionally and functionally than previously recognized.
AB - A primary virulence-associated trait of the opportunistic fungal pathogen Cryptococcus neoformans is the production of melanin pigments that are deposited into the cell wall and interfere with the host immune response. Previously, our solid-state NMR studies of isolated melanized cell walls (melanin “ghosts”) revealed that the pigments are strongly associated with lipids, but their identities, origins, and potential roles were undetermined. Herein, we exploited spectral editing techniques to identify and quantify the lipid molecules associated with pigments in melanin ghosts. The lipid profiles were remarkably similar in whole C. neoformans cells, grown under either melanizing or nonmelanizing conditions; triglycerides (TGs), sterol esters (SEs), and polyisoprenoids (PPs) were the major constituents. Although no quantitative differences were found between melanized and nonmelanized cells, melanin ghosts were relatively enriched in SEs and PPs. In contrast to lipid structures reported during early stages of fungal growth in nutrient-rich media, variants found herein could be linked to nutrient stress, cell aging, and subsequent production of substances that promote chronic fungal infections. The fact that TGs and SEs are the typical cargo of lipid droplets suggests that these organelles could be connected to C. neoformans melanin synthesis. Moreover, the discovery of PPs is intriguing because dolichol is a well-established constituent of human neuromelanin. The presence of these lipid species even in nonmelanized cells suggests that they could be produced constitutively under stress conditions in anticipation of melanin synthesis. These findings demonstrate that C. neoformans lipids are more varied compositionally and functionally than previously recognized.
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U2 - 10.1074/jbc.RA120.015201
DO - 10.1074/jbc.RA120.015201
M3 - Article
C2 - 32859751
AN - SCOPUS:85094983865
VL - 295
SP - 15083
EP - 15096
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 44
ER -