Age-dependent vascular and neurological characteristics of CADASIL are recapitulated in Notch3 mutant zebrafish, implicating a role for type IV collagen in disease progression.

CADASIL is a hereditary cerebral small vessel disease caused by NOTCH3 mutations, leading to age-dependent vascular and neurological impairments. Despite its clinical impact, the underlying pathogenic mechanisms remain poorly understood, partly because existing murine models often fail to fully replicate the broad pathological spectrum observed in humans. Here, we established and characterized a novel zebrafish (Danio rerio) model carrying the Notch3 p.C680S mutation. Our mutant zebrafish mimicked key age-related CADASIL features, including cerebrovascular dysfunction, telencephalic atrophy, cognitive impairment, and the deposition of granular osmiophilic material (GOM). Integrated transcriptomic and proteomic analyses revealed a significant downregulation of type IV collagen-related molecules, including serpinh1b, col4a1, and col4a2. These molecular findings were corroborated by immunostaining, which confirmed reduced perivascular accumulation of type IV collagen around cerebral blood vessels. Furthermore, AlphaFold 3-based structural modeling categorized the p.C680S variant as a "nonconventional" NOTCH3 mutation. These findings validate the zebrafish as a valuable vertebrate model for CADASIL and raise the possibility that diminished type IV collagen levels contribute to CADASIL pathogenesis, particularly in cases of nonconventional NOTCH3 mutations.