Sensitive bioluminescence imaging of fungal dissemination to the brain in mouse models of cryptococcosis

Liesbeth Vanherp (1, 2) , Alexandra Ristani (1, 2) , Jennifer Poelmans (1, 2) , Amy Hillen (1, 2) , Katrien Lagrou (3, 4) , Guilhem Janbon (5) , Matthias Brock (6) , Uwe Himmelreich (1, 2) , Greetje Vande Velde (2, 1)

1 Biomedical MRI [Leuven]
2 MoSAIC - core facility Molecular Small Animal Imaging Center (Leuven)
3 UCL - Université Catholique de Louvain = Catholic University of Louvain
4 Laboratory of Clinical Bacteriology and Mycology [Leuven]
5 Biologie des ARN des Pathogènes fongiques - RNA Biology of Fungal Pathogens
6 School of Life Sciences

Cryptococcus neoformans is a leading cause of fungal brain infection, but the mechanism of dissemination and dynamics of cerebral infection following pulmonary disease are poorly understood. To address these questions, non-invasive techniques that can study the dynamic processes of disease development and progression in living animal models or patients are required. As such, bioluminescence imaging (BLI) has emerged as a powerful tool to evaluate the spatial and temporal distribution of infection in living animals. We aimed to study the time profile of the dissemination of cryptococcosis from the lung to the brain in murine models by engineering the first bioluminescent C. neoformans KN99α strain, expressing a sequence-optimized red-shifted luciferase. The high pathogen specificity and sensitivity of BLI was complemented by the three-dimensional anatomical information from micro-computed tomography (μCT) of the lung and magnetic resonance imaging (MRI) of the brain. These non-invasive imaging techniques provided longitudinal readouts on the spatial and temporal distribution of infection following intravenous, intranasal or endotracheal routes of inoculation. Furthermore, the imaging results correlated strongly with the fungal load in the respective organs. By obtaining dynamic and quantitative information about the extent and timing of brain infections for individual animals, we found that dissemination to the brain after primary infection of the lung is likely a late-stage event with a timeframe that is variable between animals. This novel tool in Cryptococcus research can aid the identification of host and pathogen factors involved in this process, and supports development of novel preventive or therapeutic approaches.

Mots clés: Fungal infection; Mouse model; Pulmonary disease; Non-invasive imaging; Blood-brain barrier; Cryptococcus

Domaines: Mycologie

Liesbeth Vanherp, Alexandra Ristani, Jennifer Poelmans, Amy Hillen, Katrien Lagrou, et al.. Sensitive bioluminescence imaging of fungal dissemination to the brain in mouse models of cryptococcosis. Disease Models & Mechanisms, 2019, 12 (6), pp.dmm039123. ⟨10.1242/dmm.039123⟩. ⟨pasteur-02651287⟩