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Updated: Jun 29, 2026
Visualizing Non-lytic Exocytosis of Cryptococcus neoformans from Macrophages Using Digital Light Microscopy
Published on: October 21, 2014
Cryptococcus neoformans phospholipase B1 is critical for cryptococcoma formation in the mouse brain
Melissa E Munzen1, Glauber R de Sousa Araújo2, Mohamed F Hamed1,3
1Department of Oral Biology, University of Florida College of Dentistry, Gainesville, FL, United States.
Background:
Cryptococcus neoformans (Cn) is an encapsulated, neurotrophic fungus that can cause life-threatening meningoencephalitis in immunocompromised individuals. Phospholipase B1 (PLB1) promotes Cn adhesion and colonization, however its role in fungal biofilm formation is not entirely clear.
Methods:
We investigated how PLB1 is involved in Cn infection using a stereotaxic intracerebral infection mouse model, microscopy, whole-genome sequencing, and biophysical methods.
Results:
Our results showed that the PLB1-disrupted strain exhibited reduced survival and capsular polysaccharide (CPS) dissemination throughout brain tissue and elicited a stronger microglial response in vivo. Moreover, Cn adhesion to SH-SY5Y human neuroblastoma cells was weakened in the PLB1-disrupted strain, and in vitro biofilm formation showed reduced metabolic activity and thickness. Both the PLB1-disrupted and -reconstituted strains showed structural alterations; nevertheless, CPS production was increased in the PLB1-disrupted cells. We show that PLB1 is essential for maintaining capsular elasticity, regulating CPS secretion, and biofilm formation, which are critical for fungal colonization and cryptococcoma formation.
Conclusion:
These results emphasize the need for further investigation into the mechanisms underlying the pathogenicity of Cn. In addition, our findings provide further evidence to validate PLB1 as an important antifungal target.
Insights
Phospholipase B1 (PLB1) is crucial for Cryptococcus neoformans (Cn) brain infection. Disabling PLB1 reduces fungal survival, capsular polysaccharide spread, and biofilm formation, highlighting PLB1 as a potential antifungal target.
Area of Science:
- Mycology
- Infectious Diseases
- Neuroscience
Background:
- Cryptococcus neoformans (Cn) causes life-threatening meningoencephalitis in immunocompromised individuals.
- Phospholipase B1 (PLB1) is known to promote Cn adhesion and colonization.
- The specific role of PLB1 in fungal biofilm formation remains unclear.
Purpose of the Study:
- To investigate the role of Phospholipase B1 (PLB1) in Cryptococcus neoformans (Cn) brain infection.
- To elucidate the mechanisms by which PLB1 contributes to fungal pathogenicity and colonization.
Main Methods:
- Stereotaxic intracerebral infection mouse model.
- Microscopy and biophysical methods.
- Whole-genome sequencing of fungal strains.
Main Results:
- PLB1 disruption in Cn led to reduced fungal survival and capsular polysaccharide (CPS) dissemination in brain tissue.
- A PLB1-disrupted strain showed weakened adhesion to human neuroblastoma cells and impaired in vitro biofilm formation (reduced metabolic activity and thickness).
- PLB1 is essential for maintaining capsular elasticity, regulating CPS secretion, and biofilm formation, critical for cryptococcoma development.
Conclusions:
- PLB1 plays a critical role in Cryptococcus neoformans pathogenicity, including fungal colonization and cryptococcoma formation.
- Further research into Cn pathogenicity mechanisms is warranted.
- PLB1 is validated as a significant antifungal target.
