Single cell RNA sequencing reveals endothelial cell killing and resolution pathways in experimental malaria-associated acute respiratory distress syndrome

Plasmodium parasites cause malaria, a global health disease that is responsible for more than 200 million clinical cases and 600 000 deaths each year. Most deaths are caused by various complications, including malaria-associated acute respiratory distress syndrome (MA-ARDS). Despite the very rapid and efficient killing of parasites with antimalarial drugs, 15% of patients with complicated malaria succumb. This stresses the importance of investigating resolution mechanisms that are involved in the recovery from these complications once the parasite is killed. To study the resolution of MA-ARDS, P. berghei NK65-infected C57BL/6 mice were treated with antimalarial drugs after onset of symptoms, resulting in 80% survival. Micro-Computed Tomography revealed an altered morphology of the lungs upon infection, with an increase in total and non-aerated lung volume due to edema. Whole body plethysmography confirmed a drastically altered lung ventilation, which was restored during resolution. Single-cell RNA sequencing indicated an increased inflammatory state in the lungs upon infection, which was accompanied by a drastic decrease in endothelial cells, consistent with CD8+ T cell mediated killing. During resolution, anti-inflammatory pathways were upregulated and proliferation of endothelial cells was observed. MultiNicheNet interactome analysis provided a wealth of possible pathways that could be involved in the disease resolution, which might be interesting to functionally validate. In conclusion, promotion of pro-resolving pathways that limit inflammation and promotion of endothelial cell proliferation may be an interesting approach for the design of adjunctive treatments to promote resolution after Plasmodium parasite killing by antimalarial drugs. Cells isolated from the lungs of uninfected control mice (CON), Untreated, PbNK65-infected C57BL/6 mice dissected at 8 days post infection (d8) and ART+CQ-treated, PbNK65-infected C57BL/6 mice dissected at 12 days post infection (d12). One sample per condition (CON, d8, d12) with each sample consisting of cells pooled from 4 mice. Cells from each mouse were labelled with TotalSeq B hashtag oligo's in order to be able to distinguish the cells from the 4 mice pooled in one sample.