Integrative single cell and spatial transcriptomic analysis reveal reciprocal microglia-plasma cell crosstalk in the mouse brain during chronicTrypanosoma bruceiinfection

Abstract

Human African trypanosomiasis, or sleeping sickness, is caused by the protozoan parasite Trypanosoma brucei, and induces profound reactivity of glial cells and neuroinflammation when the parasites colonise the central nervous system. However, the transcriptional and functional responses of the brain to chronic T. brucei infection remain poorly understood. By integrating single cell and spatial transcriptomics of the mouse brain, we identified that glial responses triggered by infection are readily detected in the proximity to the circumventricular organs, including the lateral and 3rd ventricle, coinciding with the spatial localisation of both slender and stumpy forms of T. brucei. Furthermore, in silico predictions and functional validations led us to identify a previously unknown crosstalk between homeostatic Cx3cr1+ microglia and Cd138+ plasma cells mediated by IL-10 and B cell activating factor (BAFF) signalling. This study provides important insights and resources to improve understanding of the molecular and cellular responses triggered in the brain upon infection with African trypanosomes.

Light-sheet mesoscopy with the Mesolens provides fast sub-cellular resolution imaging throughout large tissue volumes

“…Airy light-sheet Mesolens imaging of cleared mouse brain is shown in Figure 6 to demonstrate the application of the method with the same specimen mounting protocol but with antibody labeling and an alternative clearing strategy ( Murakami et al., 2018 ). We imaged the forebrain region, including the dorsal and ventral 3rd ventricle, the hippocampus, the corpus callosum, and the external capsule of the caudoputamen as previous work have shown astrocytic and potential ependymal reactivity in these brain structures following infection ( Amin et al., 2009 ; Cespuglio et al., 2019 ; Quintana et al., 2022 ; Tesoriero et al., 2018 ). After deconvolution, dendrites of astrocytes and ependymal cells are clearly resolved based on the reactivity of the putative marker glial fibrillary acidic protein (GFAP), including in the corpus callosum ( Figure 6 C), circumventricular organs ( Figures 6 B–6E), and thalamus ( Figure 6 D), thus confirming that sub-cellular resolution is retained over this large FOV.…”

Immunosuppressive Mechanisms in Brucellosis in Light of Chronic Bacterial Diseases

“…Characterisation of the impact in a natural or experimental host of Brucella mutants obtained by CRISPR/Cas9 technology will be highly facilitated too. The further combination of scRNA-Seq with spatial transcriptomics has been employed to analyse immune landscapes associated with histopathological features in chronic infections, such as TB and trypanosomiasis [ 382 , 383 ]. This methodology might also help to uncover the tissue architecture and cell interactions of the Brucella -induced granuloma, as well as tertiary lymphoid structures observed in AT.…”

Single cell and spatial transcriptomic analyses reveal microglia-plasma cell crosstalk in the brain during Trypanosoma brucei infection

“…The data generated in this study have been deposited in the Gene Expression Omnibus database under accession code GSE200642. The processed transcript count data and cell metadata generated in this study are available at Zenodo (https://zenodo.org/record/ 6387555#.YwkaFi8w1nk) 103 . The flow cytometry data generated in this study are provided in the Supplementary Information/Source Data file.…”