Insights from Mural Cells for Precision Medicine in Brain Arteriovenous Malformations

About This Grant

PROJECT SUMMARY Brain arteriovenous malformations (bAVMs) are dysplastic vascular tangles that pose a significant risk for intracerebral hemorrhage (ICH). Current clinical and genetic prognostic factors remain imprecise in assessing hemorrhagic risk, underscoring the need for molecular classification. While bAVMs originate in endothelial cells, increasing evidence suggests that vascular stabilizing mural cells, such as smooth muscle cells and pericytes, are critical to bAVM stability and serve as cellular predictors of hemorrhage risk. Preliminary bulk RNA- sequencing findings from my laboratory show that mural cell depletion in adult bAVMs is associated with an aberrant immune response, whereas pediatric bAVMs exhibit unique angiogenic-like features, including Notch activation and TGFβ downregulation, suggesting an alternative mechanism of mural cell loss. This project aims to develop a multi-modal atlas of the normal and bAVM vasculature to identify non-immune, angiogenesis-centered disease mechanisms that contribute to mural cell depletion and ICH risk, providing a foundation for precision medicine strategies. The proposed research consists of two specific aims. First, an integrated cell and spatial transcriptomic atlas of the non-malformed human cortical vasculature will be created by harmonizing existing single-cell datasets and performing spatial transcriptomics on surgically resected tissues. This will provide a comprehensive reference for cerebrovascular studies and enable the identification of spatially distinct mural cell subtypes along the arteriovenous axis. Second, a multi-modal study of bAVMs across the lifespan will be conducted to elucidate age-related differences in disease mechanisms. Single-nuclei RNA/ATAC sequencing will be performed on a large cohort of pediatric and adult bAVMs to characterize gene regulatory networks (GRNs) associated with ICH risk. Additionally, an in vitro bAVM organoid model will be developed using induced pluripotent stem cells (iPSCs) carrying KRAS mutations to functionally validate the roles of Notch, TGFβ, and other identified GRNs in mural cell depletion. Targeted perturbation experiments using CRISPR activation/interference will assess the effects of these pathways on endothelial proliferation, mural cell recruitment, and vessel stability. The anticipated outcomes include a refined molecular classification of bAVMs, identification of novel biomarkers for hemorrhage risk stratification, and mechanistic insights into mural cell depletion that inform future therapeutic interventions. By leveraging integrative genomics and advanced organoid modeling, this research has the potential to transform the clinical management of bAVMs, advancing precision medicine approaches for cerebrovascular diseases. This work aligns with the broader goal of improving cerebrovascular health and reducing the global burden of stroke and ICH-related morbidity and mortality and informs precision medicine approaches to mitigate the risks of bAVM-associated hemorrhage.