Mapping endothelial-cell diversity in cerebral cavernous malformations at single cell resolution

Cerebral cavernous malformation (CCM) is a rare neurovascular disease that is characterized by enlarged and irregular blood vessels that often lead to cerebral hemorrhage. Loss-of-function mutations to any of three genes results in CCM lesion formation; namely, CCM1, CCM2, and CCM3. Here, we report for the first time in-depth single-cell RNA sequencing, combined with spatial transcriptomics and immunohistochemistry, to comprehensively characterize subclasses of brain endothelial cells under both normal conditions and after deletion of Ccm3 in a mouse model of CCM. Integrated single-cell analysis identifies arterial endothelial cells as refractory to CCM transformation. Conversely, a subset of angiogenic venous capillary endothelial cells and respective resident endothelial progenitors is at the origin of CCM lesions. These data are relevant for the understanding of the plasticity of the brain vascular system and provide novel insights into the molecular basis of CCM disease at the single cell level. Overall design: Single cell RNA-seq of brain endothelial cells from Ccm3 ko and Ccm3 wt mice, in duplicate