冷诱导蛋白RBM3对缺血性脑卒中后神经炎症反应的干预机制研究

亚低温能通过减轻缺血性脑卒中后的神经炎症反应保护神经，但降温的副作用极大限制其临床应用。冷诱导蛋白RBM3的表达能被亚低温特异性上调，而产生的神经保护作用不依赖于体温变化，故有望作为调控靶点替代亚低温疗法。本课题将研究RBM3在卒中后调节神经炎症反应的机制。本团队预实验显示，RBM3在小胶质细胞中能负向调节脂多糖诱发的炎症反应。本课题拟在小鼠体外和体内缺血性脑卒中模型中，用体视学细胞定量、双光子成像、动物行为学等手段研究：（1）RBM3调节小胶质细胞极化的机制；（2）RBM3通过调节小胶质细胞极化对神经元存活的影响；（3）RBM3通过调节小胶质细胞极化对血脑屏障完整性的作用。据此结果，我们将阐明RBM3通过抑制小胶质细胞M1促炎亚型极化并促进M2抗炎亚型极化以保护神经和血脑屏障的机制；同时将检验前期开发的新型RBM3特异性稳定剂在卒中后的保护作用，为替代亚低温治疗缺血性脑卒中开辟新的途径。

Ischemic stroke is one of the worldwide leading causes of adult death and disability. Mild to moderate therapeutic hypothermia is known as a potent tool to inhibit neuroinflammation-induced secondary damage in animal stroke model and in clinical neonatal hypoxic-ischemic encephalopathy (HIE). However, various side effects have restricted the application of therapeutic hypothermia in adult stroke patients. Therefore, it is urgent to investigate the underlying anti-neuroinflammatory mechanisms of hypothermia to bypass these limitations. While cooling suppresses global protein synthesis, a small subset of RNA-binding proteins including RBM3 is induced by hypothermia. RBM3 has been considered to be neuroprotective in diverse stressful conditions in a temperature-independent manner, which makes it as a promising therapeutic target by replacing traditional hypothermic treatment. However, it remains unclear which role RBM3 plays in post-stroke neuroinflammation. Our preliminary data have shown that RBM3 can negatively regulates lipopolysaccharide (LPS)-induced inflammatory responses in microglia. In this project, the following concerns will be addressed in both in vitro and in vivo ischemic stroke models of mice: (1) whether RBM3 regulates the polarization of microglia by promoting anti-inflammatory M2 subtype switch while suppressing pro-inflammatory M1 subtype switch; (2) whether RBM3 inhibits microglia-mediated neuronal apoptosis by triggering microglia polarization; (3) whether RBM3 inhibits microglia-mediated damage to blood brain barrier (BBB) integrity by triggering microglia polarization. Techniques including stereological cell quantification, two-photon real-time imaging and behavior tests will be applied to investigate these mechanisms. In addition, two novel small-molecule compounds have been identified to stabilize RBM3 protein structure and enhance RBM3 protein level in our pilot experiments. It is hypothesized that these compounds can inhibit neuroinflammatory responses, protect neurons and maintain BBB integrity after stroke. The study will provide an alternative treatment of hypothermia to reduce post-stroke neuroinflammation and open a new avenue for stroke therapy.