Selective vulnerability of cerebral vasculature to NOTCH3 variants in small vessel disease and rescue by phosphodiesterase-5 inhibitor.

NOTCH3 variants cause CADASIL (cerebral autosomal dominant arteriopathy and subcortical infarcts and leukoencephalopathy), the most common monogenetic form of small vessel disease (SVD) and vascular dementia (VaD). The molecular mechanisms driving CADASIL pathogenesis remain poorly understood, and no specific treatments are currently available. NOTCH3 is mainly expressed in vascular smooth muscle cells (VSMCs) that arise from different embryonic origins. Using human induced pluripotent stem cell (iPSC) models, we generated origin-specific VSMCs and found that cerebral, but not peripheral, VSMC mimics are selectively vulnerable to NOTCH3 variants. CADASIL iPSC-derived brain-specific VSMCs acquired a synthetic phenotype, accompanied with extensive extracellular matrix accumulation and impaired cell adhesion leading to anoikis. Furthermore, an endothelial-independent nitric oxide signaling was substantially impaired in CADASIL iPSC-derived VSMCs. Phosphodiesterase-5 inhibition successfully reversed the functional abnormality and survival of mutant VSMCs. Our findings uncovered mechanistic insights and suggest a viable therapeutic strategy for NOTCH3-associated SVD/VaD, reinforcing the value of patient-specific iPSCs for disease modeling and potential drug discovery.