Netrin-4 inhibits angiogenesis via binding to neogenin and recruitment of Unc5B.

Esma Lejmi (1) , Laurence Leconte (1) , Sandrine Pédron-Mazoyer (1) , Stanislas Ropert (1) , William Raoul (2) , Sophie Lavalette (2) , Ilyes Bouras (1) , Jean-Guillaume Feron (1) , Martine Maitre-Boube (1) , Franck Assayag (3) , Charles Feumi (2) , Monica Alemany (1) , Tan Xian Jie (1) , Tatyana Merkulova (1) , Marie-France Poupon (3, 4) , Marie-Magdeleine Ruchoux (1) , Gérard Tobelem (1) , Florian Sennlaub (2) , Jean Plouët (1)

1 Centre de Recherche Cardiovasculaire de Lariboisiere
2 CRC (UMR_S 872) - Centre de Recherche des Cordeliers
3 DIGBFC - Dynamique de l'information génétique : bases fondamentales et cancer
4 Laboratoire de Recherche Translationnelle

Netrins are secreted molecules with roles in axon guidance and angiogenesis. We identified Netrin-4 as a gene specifically overexpressed in VEGF-stimulated endothelial cells (EC) in vitro as well as in vivo. Knockdown of Netrin-4 expression in EC increased their ability to form tubular structures on Matrigel. To identify which receptor is involved, we showed by quantitative RT-PCR that EC express three of the six Netrin-1 cognate receptors: neogenin, Unc5B, and Unc5C. In contrast to Netrin-1, Netrin-4 bound only to neogenin but not to Unc5B or Unc5C receptors. Neutralization of Netrin-4 binding to neogenin by blocking antibodies abolished the chemotactic effect of Netrin-4. Furthermore, the silencing of either neogenin or Unc5B abolished Netrin-4 inhibitory effect on EC migration, suggesting that both receptors are essential for its function in vitro. Coimmunoprecipitation experiments demonstrated that Netrin-4 increased the association between Unc5B and neogenin on VEGF- or FGF-2-stimulated EC. Finally, we showed that Netrin-4 significantly reduced pathological angiogenesis in Matrigel and laser-induced choroidal neovascularization models. Interestingly, Netrin-4, neogenin, and Unc5B receptor expression was up-regulated in choroidal neovessel EC after laser injury. Moreover, Netrin-4 overexpression delayed tumor angiogenesis in a model of s.c. xenograft. We propose that Netrin-4 acts as an antiangiogenic factor through binding to neogenin and recruitment of Unc5B.

Domaines: Biologie cellulaire; Organes des sens

Esma Lejmi, Laurence Leconte, Sandrine Pédron-Mazoyer, Stanislas Ropert, William Raoul, et al.. Netrin-4 inhibits angiogenesis via binding to neogenin and recruitment of Unc5B.. Proceedings of the National Academy of Sciences of the United States of America, 2008, 105 (34), pp.12491-6. ⟨10.1073/pnas.0804008105⟩. ⟨inserm-00315946⟩