Multiomic profiling reveals pericyte and smooth muscle cell contributions to CADASIL pathology in cell-specific Notch3 mutant mice

Cerebral ischemic small vessel disease (SVD) is the leading cause of vascular dementia and a major contributor to stroke. Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is the most common monogenic form of familial SVD. CADASIL is caused by dominant missense mutations in Notch3, a receptor expressed in mural cells, including smooth muscle cells (SMCs) and pericytes. However, the cell-type specific contributions driving the CADASIL pathology remain unknown due to lack of animal models. Here, we generated two conditional knock-in mouse models carrying the CADASIL-causing Notch3R170C mutation selectively in SMC and brain pericytes. Both Notch3R170C models showed perivascular accumulation of the NOTCH3 extracellular domain, yet developed distinct neurovascular changes depending on the affected cell type. Pericyte-specific Notch3R170C mice displayed pronounced region-selective microglial activation and vascular changes, whereas SMC-specific Notch3R170C mice showed localized perivascular gliosis with minimal vascular remodeling. Proteomic profiling of isolated brain vessels revealed largely unique cell-specific responses. Pericytes Notch3R170C expression dysregulated metabolic pathways, whereas SMC Notch3R170C expression induced immune signaling related pathways. Integration with single-cell RNA-seq data revealed that many of the proteomic and phosphoproteomic shifts might also include brain endothelial cells, including metabolic changes in the presence of pericyte Notch3R170C and inflammatory signaling in the presence of SMC-Notch3R170C. Together, these findings define mural cell-specific mechanisms that contribute to the CADASIL-associated vascular pathology.