A dissemination-prone morphotype enhances extrapulmonary organ entry by the fungus<i>Cryptococcus neoformans</i>

Denham, Steven T; Brammer, Brianna; Chung, Krystal; Wambaugh, Morgan A.; Bednarek, Joseph; Guo, Li; Brown, Jessica C. S.

doi:10.1101/2020.08.27.270843

Cited by 2 publications

(2 citation statements)

References 149 publications

(250 reference statements)

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“…Quantification was performed using a FACS ARIA III (BD) cytometer with analysis on the Cytobank platform. A total of 20,000 events were recorded, and doublets were filtered out using comparisons of forward-scatter width (FSC-W) versus forward-scatter height (FSC-H) to exclude events with high FSC-W and FSC-H. To define the 1C and 2C gates, cells were grown in yeast nitrogen base (YNB) (24 h, 30°C, 150 rpm) without or with 80 μg/ml benomyl, which traps cells in 2C, as recently reported ( 106 ).…”

Section: Methodsmentioning

confidence: 99%

The Transcription Factor Pdr802 Regulates Titan Cell Formation and Pathogenicity of Cryptococcus neoformans

Reuwsaat

Agustinho

Motta

et al. 2021

mBio

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Cryptococcus neoformans is a ubiquitous, opportunistic fungal pathogen that kills almost 200,000 people worldwide each year. It is acquired when mammalian hosts inhale the infectious propagules; these are deposited in the lung and, in the context of immunocompromise, may disseminate to the brain and cause lethal meningoencephalitis. Once inside the host, C. neoformans undergoes a variety of adaptive processes, including secretion of virulence factors, expansion of a polysaccharide capsule that impedes phagocytosis, and the production of giant (Titan) cells. The transcription factor Pdr802 is one regulator of these responses to the host environment. Expression of the corresponding gene is highly induced under host-like conditions in vitro and is critical for C. neoformans dissemination and virulence in a mouse model of infection. Direct targets of Pdr802 include the quorum sensing proteins Pqp1, Opt1, and Liv3; the transcription factors Stb4, Zfc3, and Bzp4, which regulate cryptococcal brain infectivity and capsule thickness; the calcineurin targets Had1 and Crz1, important for cell wall remodeling and C. neoformans virulence; and additional genes related to resistance to host temperature and oxidative stress, and to urease activity. Notably, cryptococci engineered to lack Pdr802 showed a dramatic increase in Titan cells, which are not phagocytosed and have diminished ability to directly cross biological barriers. This explains the limited dissemination of pdr802 mutant cells to the central nervous system and the consequently reduced virulence of this strain. The role of Pdr802 as a negative regulator of Titan cell formation is thus critical for cryptococcal pathogenicity. IMPORTANCE The pathogenic yeast Cryptococcus neoformans presents a worldwide threat to human health, especially in the context of immunocompromise, and current antifungal therapy is hindered by cost, limited availability, and inadequate efficacy. After the infectious particle is inhaled, C. neoformans initiates a complex transcriptional program that integrates cellular responses and enables adaptation to the host lung environment. Here, we describe the role of the transcription factor Pdr802 in the response to host conditions and its impact on C. neoformans virulence. We identified direct targets of Pdr802 and also discovered that it regulates cellular features that influence movement of this pathogen from the lung to the brain, where it causes fatal disease. These findings significantly advance our understanding of a serious disease.

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Section: Methodsmentioning

confidence: 99%

The Transcription Factor Pdr802 Regulates Titan Cell Formation and Pathogenicity of Cryptococcus neoformans

Reuwsaat

Agustinho

Motta

et al. 2021

mBio

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“…2 Multiple in vitro conditions induce the growth of cryptococcal capsule. [5][6][7][8][9][10] Conditions that reflect aspects of the mammalian host environment are of particular interest, such as those that include tissue culture medium (TCM) or mammalian serum 9 , human body temperature (37°), host-like CO2 concentrations (~5%) 6 , host-like pH (7.35-7.45), 6,[9][10][11][12] and nutrient limitations typical of the host environment. 7 We have previously shown that transcription is required for capsule growth.…”

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confidence: 99%

Leveraging a new data resource to define the response ofC. neoformansto environmental signals

Jung

Kang

Brown

et al. 2023

Preprint

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Cryptococcus neoformans is an opportunistic fungal pathogen with a polysaccharide capsule that becomes greatly enlarged in the mammalian host and during in vitro growth in response to host-like conditions. To understand how individual host-like signals affect capsule size and gene expression, we grew cells with and without all combinations of 5 signals suspected of affecting capsule size and systematically measured cell and capsule sizes of 26,275 cells. We also collected samples for RNA-Seq at 30, 90, 180, and 1440 minutes and carried out RNA-Seq in quadruplicate, yielding 881 RNA-Seq samples. This massive, uniformly collected dataset will be a significant resource for the research community. Analysis revealed that capsule induction requires both tissue culture medium and either CO2 or exogenous cyclic AMP, a second messenger. Rich medium (YPD) blocks capsule growth completely, DMEM permits it, and RPMI yields the largest capsules. Medium has the biggest impact on overall gene expression, followed by CO2, mammalian body temperature (37C compared to 30C), and then cAMP. Surprisingly, adding CO2 or cAMP pushes overall gene expression in the opposite direction from tissue culture media, even though both tissue culture medium and CO2 or cAMP are required for capsule development. By modeling the relationship between gene expression and capsule size, we identified novel genes whose deletion affects capsule size.

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A dissemination-prone morphotype enhances extrapulmonary organ entry by the fungusCryptococcus neoformans

Cited by 2 publications

References 149 publications

The Transcription Factor Pdr802 Regulates Titan Cell Formation and Pathogenicity of Cryptococcus neoformans

The Transcription Factor Pdr802 Regulates Titan Cell Formation and Pathogenicity of Cryptococcus neoformans

Leveraging a new data resource to define the response ofC. neoformansto environmental signals

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