Nidogen-2 Maintains the Contractile Phenotype of Vascular Smooth Muscle Cells and Prevents Neointima Formation via Bridging Jagged1-Notch3 Signaling.

BACKGROUND

How the extracellular matrix (ECM) microenvironment modulates the contractile phenotype of vascular smooth muscle cells (VSMCs) and confers vascular homeostasis remains elusive.

METHODS

To explore the key ECM proteins in the maintenance of the contractile phenotype of VSMCs, we applied protein-protein interaction network analysis to explore novel ECM proteins associated with the VSMC phenotype. By combining in vitro and in vivo genetic mice vascular injury models, we identified nidogen-2, a basement membrane glycoprotein, as a key ECM protein for maintenance of vascular smooth muscle cell identity.

RESULTS

We collected a VSMC phenotype-related gene dataset by using Gene Ontology annotation combined with a literature search. A computational analysis of protein-protein interactions between ECM protein genes and the genes from the VSMC phenotype-related gene dataset revealed the candidate gene nidogen-2, a basement membrane glycoprotein involved in regulation of the VSMC phenotype. Indeed, nidogen-2-deficient VSMCs exhibited loss of contractile phenotype in vitro, and compared with wild-type mice, nidogen-2 mice showed aggravated post-wire injury neointima formation of carotid arteries. Further bioinformatics analysis, coimmunoprecipitation assays, and luciferase assays revealed that nidogen-2 specifically interacted with Jagged1, a conventional Notch ligand. Nidogen-2 maintained the VSMC contractile phenotype via Jagged1-Notch3 signaling but not Notch1 or Notch2 signaling. Nidogen-2 enhanced Jagged1 and Notch3 interaction and subsequent Notch3 activation. Reciprocally, Jagged1 and Notch3 interaction, signaling activation, and Jagged1-triggered VSMC differentiation were significantly repressed in nidogen-2-deficient VSMCs. In accordance, the suppressive effect of Jagged1 overexpression on neointima formation was attenuated in nidogen-2 mice compared with wild-type mice.

CONCLUSIONS

Nidogen-2 maintains the contractile phenotype of VSMCs through Jagged1-Notch3 signaling in vitro and in vivo. Nidogen-2 is required for Jagged1-Notch3 signaling.