Single-cell and spatial transcriptomic analyses reveal transcriptional cell lineage heterogeneity in extracranial arteriovenous malformation.

Background: Extracranial arteriovenous malformations (eAVMs) are rare congenital vascular anomalies consisting of abnormal artery-vein bypass with no intervening capillary network, and can lead to disability and death. The critical genetic determination factors and key transcriptional pathways of the eAVMs genesis process are still unclear.

Objective: To generate an overview of the molecular information within eAVMs at the single-cell level.

Methods: We performed single-cell RNA sequencing (scRNA-seq) on nine samples of eAVMs receiving a confirmatory histopathologic evaluation from a board-certified dermatopathologist and two nonlesional tissue sample controls. 10x Visium spatial transcriptomics (ST) was performed on one eAVM to spatially localize heterogeneous cells and profile the gene expression dynamics of the cells in their morphological context. The scRNA-seq and ST data were integrated and analyzed to further query for spatially restricted mapping of intrapopulation heterogeneous cells.

Results: We identified different cell states of endothelial cells (ECs), perivascular cells and immune cells in eAVMs, uncovered the presence of MAFB+ nidus ECs, characterized mesenchymal activation in ECs, and identified transcriptional variation within perivascular cells and the presence of smooth muscle-like pericytes in eAVMs. Dysregulated cell to cell interactions among ECs, perivascular cells and immune cells that are associated with eAVMs, including those involving MDK, VEGF, ANGPT, SEMA3 and GALECTIN-9 were cataloged. Together, our results depicted the heterogeneity underlying cell function and interaction of eAVMs at a single-cell resolution.

Conclusion: We present a comprehensive picture of the cell-resolution atlas that describes the transcriptomic heterogeneity underlying cell function and interaction in eAVMs.