Protein S对脑出血的保护作用及机制

Spontaneous intracerebral hemorrhage (ICH) is a devastating disease with high rate of mortality and disability，thrombin is the leading cause of brain edema and death after intracerebral hemorrhage. Protein S is not only an inhibitor of prothrombinase which transform prothrombin to thrombin, but also the substrate of thrombin. Our preliminary results showed that Protein S was available to attenuate brain delayed injury after intracerebral hemorrhage, We will further explore the underlying mechanism. WE will apply several methods to test the effect of Protein S on blood-brain barrier permeability, brain edema, brain injury volume, degenerating neurons and neurological function, and prove that Protein S reduce brain edema through protecting blood-brain barrier delayed injury, ultimately attenuate delayed brain injury. Subsequently, we will utilize multiple technologies to detect the effect of Protein S on thrombin’s generation and thrombin’s activity, and proved that Protein S inhibits extracellular matrix components degradation and intercellular distance enlargement through suppressing PAR-1's cleavage by thrombin and inactivating downstream path PAR-1-RhoA-MMP-9 and PAR-1-RhoA-ROCK2-MLC, ultimately decreases BBB permeability. We hope that our innovative study would be beneficial for the advancement in prevention, diagnosis and therapy of ICH.

脑出血是高致死性和高致残性的脑血管病，凝血酶是导致脑出血后脑水肿及病人死亡的重要原因。Protein S不仅是凝血酶生成的抑制剂，同时也是凝血酶的底物。本项目前期研究结果提示Protein S对脑出血具有保护作用，我们计划进一步明确该作用并探讨其具体作用机制。本项目通过检测Protein S对脑出血后血脑屏障通透性、脑水肿、继发性脑损伤的影响，证明Protein S通过保护血脑屏障减轻脑水肿进而减少脑出血继发性脑损伤。通过检测Protein S对凝血酶生成、活性及下游通路的影响，阐明Protein S不仅通过抑制凝血酶生成，还通过抑制凝血酶剪切激活PAR-1受体抑制血脑屏障组分降解和缩短微血管内皮细胞间隙，起到降低血脑屏障通透性的作用。本项目为发现脑出血的潜在治疗靶点提供科学依据，研究内容具有源头创新性和重要临床意义。

脑出血是临床关注的医学难题，但至今缺乏有效的防治手段。Protein S是血管内皮细胞中对血管功能起重要调控作用的生物分子，其数量、结构和功能异常会导致脑血管病。目前国内外极少报道Protein S对脑出血的作用。脑出血后血管内皮细胞受损，炎症细胞等炎症介质进入神经中枢进一步破会血脑屏障，从而加重脑水肿和神经损伤。本项目的研究目的是探讨Protein S对脑出血的作用和机制。本项目首先发现 Protein S减少脑出血后血脑屏障通透性、脑水肿、脑损伤体积、神经元变性和神经功能损伤，Protein S抗体则起到相反的作用。实验进一步发现 Protein S有对抗凝血酶导致的血脑组分(ZO-1, Claudin-5, Ocluddin)降解、血脑屏障损伤、脑水肿，此作用可能通过RhoA-PAKT-MMP-9途径。此外本项目结果还说明 Protein S可以减少促炎症因子IL-6,TNF-α水平, 减轻小胶质细胞激活和中性粒细胞脑组织浸润。以上结果表明Protein S对脑出血具有保护作用，其作用可能是通过抑制RhoA-PAKT-MMP-9途径介导的血脑屏障组分降解及炎症反应减轻BBB破坏，从而减轻脑水肿和脑实质损伤。本项目通过阐明Protein S在脑出血疾病中的神经保护作用及分子机制， 期望为脑出血疾病的预防、临床诊断和治疗药物开发提供新的思路。