Application of Light-Sheet Mesoscopy to Image Host-Pathogen Interactions in Intact Organs

Area of Science:

• Neuroscience
• Parasitology
• Biomedical Imaging

Background:

• Human African Trypanosomiasis (HAT) is a parasitic disease affecting the central nervous system (CNS).
• Current methods for studying infection-induced neuroinflammation in HAT are limited to small brain regions.
• Understanding structural brain changes during HAT is crucial for disease progression and treatment.

Purpose of the Study:

• To investigate the structural changes in the mouse brain during chronic Human African Trypanosomiasis (HAT) infection.
• To evaluate the utility of light-sheet mesoscopy for imaging neuroinflammation at a cellular level in cleared mouse brains.
• To characterize the spatial distribution and morphology of astrocyte responses to *Trypanosoma brucei* infection.

Main Methods:

• Utilized a novel light-sheet illuminator combined with a Mesolens objective for large-volume, sub-cellular resolution imaging.
• Cleared chronically infected mouse brains using CUBIC+ and performed antibody staining for Glial Fibrillary Acid Protein (GFAP).
• Analyzed morphometrics and spatial distribution of GFAP+ cells to assess neuroinflammation and gliosis.

Main Results:

• Detected a significant increase in GFAP+ cell dendrite branching around the lateral and third ventricles in infected mice.
• Observed a negative correlation between astrocyte branching near ventricles and distal sites.
• Demonstrated the capability of light-sheet mesoscopy to resolve cellular inflammatory responses in intact, cleared organs.

Conclusions:

• Light-sheet mesoscopy is a powerful tool for studying host-pathogen interactions in the brain at the cellular level.
• Parasitic infection by *Trypanosoma brucei* induces localized astrocyte reactivity around circumventricular spaces in the mouse brain.
• This study opens new avenues for mesoscale imaging techniques in neuroparasitology.