Mechanisms and therapeutic targets of neurovascular injury in hyperglycemic stroke

尽管30%的中风患者是糖尿病患者，并且超过50%的中风患者发展为中风后高血糖症（HG）， 在急性中风情况下血糖正常化的临床益处是有问题的， 低血糖此外，糖尿病和HG均与更差的神经功能结局、更低的 再灌注治疗效果差，血管并发症加重。因此，迫切需要 确定新的治疗目标，以减轻这些风险。我们的长期目标是 确定合适的药物靶点，以帮助发现新的和临床上适用的治疗方法， 卒中结局。本申请的目的是确定内皮-TXNIP在高血糖中的作用。 中风引起的神经血管损伤硫氧还蛋白相互作用蛋白（TXNIP），一种主要的细胞内调节因子 氧化还原/葡萄糖诱导的应激和炎症，现在已知在中风中上调， 有希望的治疗靶点。在初步研究中，我们已经证明，HG小鼠具有较高的TXNIP， 与野生型（WT）对照相比，在栓塞性中风后表达和出血增加。这些 令人兴奋的研究结果表明，TXNIP作为一个有前途的治疗脑卒中的目标。然而，在这方面， 关于血管TXNIP对炎症反应的特异性作用， 缺血再灌注（tPA）损伤的反应。因此，我们的中心假设是HG/再灌注- 诱导的TXNIP表达通过激活NLRP 3-炎性体、血管内皮细胞和血管内皮细胞来维持神经血管损伤。 血管内皮生长因子（VEGF）和基质金属蛋白酶（MMP）。这一假设将是 在三个具体方面进行了测试：目的1：测试HG通过激活血管内皮细胞而加重再灌注损伤的假设。 脑卒中后TXNIP-NLRP 3炎性小体。目的2：检验高血糖性卒中诱导的 TXNIP触发VEGF和MMP介导的神经血管损伤。目标3：检验一部小说 TXNIP抑制剂减轻高血糖卒中诱导的神经血管损伤和功能缺陷 本研究的预期结果包括：（1）高血糖性脑卒中的识别- TXNIP作为NLRP 3炎性小体形成的关键介质，以及（2）证明高血糖卒中 诱导的TXNIP-NLRP 3触发VEGF和MMP介导的神经血管损伤，使用内皮特异性 （EC）-TXNIP-/-小鼠，特异性NLRP 3、MMP-9/2和VEGF抑制剂，并用IV-tPA再灌注（1.5小时）。（三） 我们的研究将是第一个使用新创建的TXNIP和NLRP 3特异性抑制剂来解决 TXNIP的治疗性抑制是否会改善缺血半暗带的长期恢复和程度 通过在栓塞性中风中使用MRI-扩散张量成像（DTI）。这些研究可能具有深远的意义。 作为继发性损伤的关键介质， 为HG/糖尿病相关的脑卒中神经血管损伤的治疗干预提供了新的靶点。

Although 30% of patients with stroke are diabetic, and over 50% develop post-stroke hyperglycemia (HG), the clinical benefit of glucose normalization in the acute stroke setting is problematic controversial due to the risk of hypoglycemia. Moreover, both diabetes and HG are associated with worse neurological outcomes, lower reperfusion therapies efficacy, and aggravated vascular complications. Hence, there is an urgent need to identify novel targets for the development of treatments that mitigate these risks. Our long-term goal is to identify suitable drug targets to aid in the discovery of novel and clinically applicable therapies for improving stroke outcome. The objective of this application is to determine the role of endothelial-TXNIP in hyperglycemic stroke-induced neurovascular damage. Thioredoxin-interacting protein (TXNIP), a major intracellular regulator of redox/ glucose induced stress and inflammation, now known to be upregulated in stroke, presents a promising therapeutic target. In preliminary studies, we have demonstrated that HG mice have higher TXNIP expression and increased hemorrhage after an embolic stroke compared to wild type (WT) controls. These exciting findings have suggested that TXNIP as a promising therapeutic target in cerebral stroke. However, there are definite knowledge gaps concerning the specific contribution of vascular TXNIP to the inflammatory response in ischemia and reperfusion (tPA) injury. Therefore, our central hypothesis is that HG/ reperfusion- induced TXNIP expression sustains neurovascular injury through activation of NLRP3-inflammasome, vascular endothelial growth factor (VEGF), and matrix metalloproteinase (MMP) after stroke. This hypothesis will be tested in three specific: Aim 1: Test the hypothesis that HG exacerbates reperfusion injury by activating the TXNIP-NLRP3 inflammasome after stroke. Aim 2: Test the hypothesis that hyperglycemic stroke-induced TXNIP triggers VEGF and MMP mediated neurovascular damage. Aim 3: Test the hypothesis that a novel TXNIP inhibitor attenuates hyperglycemic stroke-induced neurovascular damage and functional deficits. Expected outcomes of the proposed research include: (1) Identification of hyperglycemic stroke induced- TXNIP as a key mediator of NLRP3 inflammasome formation, and (2) demonstration that hyperglycemic stroke induced-TXNIP-NLRP3 triggers VEGF and MMP-mediated neurovascular damage, using endothelial specific (EC)-TXNIP-/- mice, a specific NLRP3, MMP-9/2 and VEGF inhibitors, and reperfusion with IV-tPA (1.5 h). (3) Our study will be the first to use of the newly created specific inhibitors for TXNIP and NLRP3 to address whether therapeutic inhibition of TXNIP will improve long-term recovery and extent of the ischemic penumbra by using MRI-diffusion tensor imaging (DTI) in an embolic stroke. These studies may have far-reaching translational implications as the identification of vascular TXNIP, as key mediators of secondary injury will provide novel targets for therapeutic intervention in HG/diabetes associated neurovascular injury in stroke.