Nogo-A/S1PR2与Notch1相互作用调控自噬对脑梗死远隔部位血管新生及神经损害的作用机制

脑梗死远隔部位继发性损害是阻碍神经功能恢复的重要原因，而促进血管新生对远隔损害具有保护作用。我们前期研究发现抑制Nogo-A可减轻脑梗死后远隔损害，但Nogo-A如何参与远隔损害不清楚。Notch是血管发育的重要调节分子，体外研究发现Notch可调控Nogo-A通路。我们预实验发现，Nogo-A受体S1PR2及其下游调控因子Notch1在脑梗死后远隔部位血管上表达升高，且自噬相关蛋白Beclin1及LC3在Notch1、S1PR2表达细胞同时增多。我们推测Nogo-A/S1PR2与Notch1作用介导自噬通路抑制脑梗死远隔部位血管新生，加重远隔损害。本项目拟基于脑梗死模型，采用慢病毒基因沉默、激酶抑制剂或受体激动剂等方法，阐明Nogo-A/S1PR2与Notch1相互作用调控Beclin1相关的细胞自噬在脑梗死后远隔部位血管新生及神经损害中的作用，为脑梗死远隔损害新的防治靶点提供科学依据。

Neurodegeneration in remote areas secondary to cortical infarction plays a vital role in the post-stroke functional recovery. Our studies have revealed that promoting angiogenesis in remote areas ameliorates the secondary neurodegeneration. The exact mechanisms of angiogenesis in remote area after cortical infarction need further elucidation. We have demonstrated that inhibition of Nogo-A expression could rescue the neuronal regeneration in remote areas after cortical infarction. However, it is unclear how Nogo-A acts as the detrimental effect on the remote damage following cerebral infarction. Notch has been shown to play a vital role in vascular remodeling. Recent evidence shows possible interactions of Notch activation with actions of Nogo-A signaling in vitro. Our preliminary results showed that S1PR2, one receptor of Nogo-A, was upregulated in cerebral blood vessels of remote areas, which was accompanied by an elevation of Notch1 levels. We further observed that S1PR2- and Notch1-positive endothelial cells also showed increased expression of Beclin1 and LC3, the markers for occurrence of autophagy. Based on the above preliminary results, we hypothesized that Nogo-A/S1PR2 interacts with Notch1 to inhibit the process of angiogenesis by induction of autophagic activation, which resultantly leads to the neuronal damage secondary to cerebral infarction. In the proposal, using experimental ischemic models with middle cerebral artery occlusion, we designed to investigate how Nogo-A/S1PR2 pathway interacts with Notch1 to modulate Beclin1-mediated autophagy during angiogenesis in the remote areas by means of siRNA-mediated knockdown of Nogo-A gene, specific kinase inhibitor and receptor agonist. The findings will provide further scientific insights into the potential targets for rescuing the secondary neurodegeneration after ischemic stroke.