AIT webinar series – Lung single cell transcriptomics to guide the development for AOP anchored-cell based assays in response to nanoparticle exposure.

Event Date: February 27th 15:02 - 27th 16:02 2023

Sponsored by the British Toxicology Society (BTS)
Tobias Stoger (Helmholtz, Germany)

Inhaled nanoparticles (NP) can cause acute and chronic inflammation. Here we seek to identify NP-specific cellular perturbation pathways and the underlying key cell types to inform adverse outcome pathway (AOP) anchored in vitro studies, by single cell transcriptomics. We exposed mice intratracheally to carbon black (CNP), tangled double-walled (DWCNT) and rigid, multi-walled carbon nanotubes (MWCNT). All lungs underwent singlecell RNA sequencing (scRNA-seq), histology and BAL analysis.

At the chosen doses all NPs caused comparable airspace neutrophilia at 12h, which increased until d6 for the CNTs but remained elevated until d28 only for MWCNT, indicating the key event (KE) acute and chronic inflammation.

Comparing scRNA-seq and BAL cytokine levels at 12h, NPs specifically differentiated the fate of inflammation. In agreement with airspace neutrophilia, CNP uniquely triggered GM-CSF and CXCL1 protein release, with Csf2 and Cxcl1 mRNAs being expressed mainly in alveolar epithelial cells. DWCNT caused CCL2, -3 and -4 release involving interstitial macrophages and monocytes, associated with high BAL macrophage numbers at d6 in turn. MWCNT in contrast caused an ample BAL cytokine increase involving different cell types and specifically caused a Th2 cytokine response (CCL11, IL10), a crucial KE of fibrosis AOPs. Cell communication analysis uncovered an early (12h) distinct signaling centered around alveolar macrophages only for DWCNT, and between epithelial cells, adjacent fibroblasts and monocyte derived phagocytes for CNPs, whereas MWCNT triggered a broad network including epithelial cells, fibroblasts, macrophages, dendritic cells and endothelial cells.

Our study uncovers early NP-specific cell perturbations and identified first specific cellular response pattern which can guide AOP predictive cell-based testing strategies. Further analysis of the cellular dynamics shall enhance our understanding of NP specific cell circuits and related pathologies.

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