Brain Research Institute, University of Zurich and Department of Health Sciences and Technology, Swiss Federal Institute of Technology (ETH) Zurich, 8057 Zurich, Switzerland.
Department of Neuroscience, Neuroscience Institute Cavalieri Ottolenghi (NICO), Università degli Studi di Torino, Orbassano, Turin 10043, Italy.
Dev Cell. 2017 Oct 9;43(1):24-34.e5. doi: 10.1016/j.devcel.2017.08.014. Epub 2017 Sep 21.
Heparan sulfate proteoglycans (HSPGs) critically modulate adhesion-, growth-, and migration-related processes. Here, we show that the transmembrane protein, Nogo-A, inhibits neurite outgrowth and cell spreading in neurons and Nogo-A-responsive cell lines via HSPGs. The extracellular, active 180 amino acid Nogo-A region, named Nogo-A-Δ20, binds to heparin and brain-derived heparan sulfate glycosaminoglycans (GAGs) but not to the closely related chondroitin sulfate GAGs. HSPGs are required for Nogo-A-Δ20-induced inhibition of adhesion, cell spreading, and neurite outgrowth, as well as for RhoA activation. Surprisingly, we show that Nogo-A-Δ20 can act via HSPGs independently of its receptor, Sphingosine-1-Phosphate receptor 2 (S1PR2). We thereby identify the HSPG family members syndecan-3 and syndecan-4 as functional receptors for Nogo-A-Δ20. Finally, we show in explant cultures ex vivo that Nogo-A-Δ20 promotes the migration of neuroblasts via HSPGs but not S1PR2.
硫酸乙酰肝素蛋白聚糖(HSPGs)对细胞黏附、生长和迁移相关过程起关键调控作用。本研究显示,跨膜蛋白神经生长抑制因子-A(Nogo-A)通过 HSPGs 抑制神经元和 Nogo-A 反应性细胞系的轴突生长和细胞铺展。Nogo-A 的胞外活性 180 个氨基酸区域,命名为 Nogo-A-Δ20,可与肝素和脑源性硫酸乙酰肝素糖胺聚糖(HSAGs)结合,但不能与密切相关的软骨素硫酸糖胺聚糖结合。HSPGs 是 Nogo-A-Δ20 诱导的黏附、细胞铺展和轴突生长抑制以及 RhoA 激活所必需的。令人惊讶的是,我们发现 Nogo-A-Δ20 可通过 HSPGs 独立于其受体(鞘氨醇-1-磷酸受体 2(S1PR2))发挥作用。因此,我们确定 HSPG 家族成员 syndecan-3 和 syndecan-4 是 Nogo-A-Δ20 的功能性受体。最后,我们在离体培养物中显示,Nogo-A-Δ20 通过 HSPGs 而非 S1PR2 促进神经前体细胞的迁移。