如何提高缺血性脑卒中后tPA溶栓和血流再通的效率，一直是困扰医学界的难题。我们前期研究证明，重组ADAMTS13可降低脑缺血后tPA溶栓引起的脑出血。我们近期预实验发现，重组ADAMTS13可促进tPA的溶栓效果并减轻脑缺血损伤，然而其作用途径和机制仍有待研究。血管周细胞-内皮系统对调控脑血管功能和脑血流发挥关键作用。基于前期研究结果，本项目拟采用脑缺血模型，结合体外脑血管周细胞和内皮细胞低氧再氧化模型，借助基因敲除、基因沉默、重组蛋白、多光子显微镜活体脑血管成像、核磁共振等多种手段，研究重组ADAMTS13促进tPA溶栓的有效途径，阐明重组ADAMTS13通过干预VWF途径，调控tPA-NR2B偶联介导的细胞生存和死亡信号传导，减轻tPA对周细胞-内皮系统的损害，保护脑微血管，从而增强tPA的溶栓效果并改善脑血流。这些研究将为延长tPA的治疗时间窗，扩大其临床应用提供新的思路和理论依据。

Thrombolytic therapy with tissue plasminogen activator (tPA) for acute ischemic stroke improves neurologic outcome, but the degree of improvement is still unsatisfactory. Thus, there remains a clear need to identify new therapeutic strategies to enhance the efficacy of tPA thrombolysis and improve cerebral blood flow restoration. Pericytes have recently come into focus as critical regulators of the blood-brain barrier integrity and microcirculatory blood flow. Recently, we have demonstrated that recombinant ADAMTS13 (rADAMTS13) reduced tPA-related cerebral hemorrhage after ischemic stroke. Our preliminary data show that rADAMTS13 significantly promoted tPA-induced thrombolysis and reduced ischemic brain injury in a mouse model of stroke. In this project, we will further assess the mechanism of rADAMTS13 and tPA combination therapy after ischemic stroke. We will employ mouse stroke model, cerebral pericytes and endothelial cells cultures, using VWF and ADAMTS13 knockout mice, VWF siRNA, ADAMTS13 siRNA, rADAMTS13, multi-photon confocal microscopy, high-field MRI, and molecular biological approaches to determine whether the inhibition of direct binding of tPA and NMDA receptor NR2B and consequent NR2B activation by treatment with rADAMTS13 is responsible for further changes in cell death signaling and cell survival pathway, and whether these effects contribute to the survival of pericytes and endothelial cells and function of microvessel after ischemic stroke. We will also determine the effects of rADAMTS13 and tPA combination therapy on tPA-induced cerebral blood flow restoration as well as on extending the therapeutic time window of tPA after ischemic stroke. These proposed studies may provide novel insights into improving thrombolytic therapy for the clinical treatment of acute ischemic stroke.