Scalable and multimodal brain angiogenesis and blood-brain barrier genetics by somatic mutagenesis

The endothelial blood-brain barrier (BBB) is a multi-cellular structure essential for neuroprotection and the maintenance of brain homeostasis. BBB dysfunction has been associated with a multitude of neurological disorders. Despite its clinical relevance, our understanding of BBB regulation remains fragmentary, owing to low-throughput Mendelian approaches utilized to study BBB genetics in the zebrafish and mouse model systems. Vertebrate BBB development begins during embryonic stages with the invasion of angiogenic sprouts from the perineural endothelium into the brain parenchyma, a process also known as brain angiogenesis. The optical clarity and external development of the zebrafish embryos, along with a high degree of conservation between angiogenic programs in zebrafish and mice, make zebrafish an attractive model system to investigate brain angiogenesis. On the other hand, dissimilarities in the glial-endothelial interactions and the loss of natural transparency before BBB maturation make zebrafish a less suitable model system to study BBB permeability. Furthermore, the development of recombinant AAVs with high BBB tropism in vivo facilitates rapid assessment of BBB permeability in mice. Here, we combine somatic CRISPR-Cas9 gene disruption strategies in zebrafish and mice to achieve rapid and multimodal analysis of gene function in brain angiogenesis and BBB permeability.