COMPLEMENT-MEDIATED NEURONAL INJURY IN STROKE

描述(摘自申请者摘要)：缺血性中风是 死亡和残疾，这些疾病的治疗选择非常有限。这个 实现快速发展的相反目标造成的治疗困境 再灌注和预防脑出血(ICH)，已经引导我们 考虑一下针对炎症性范例的效用，补体 CASCADE，用于缺血性中风的抑制。研究是由 补体激活直接导致脑损伤的假说 并可能间接降低tPA的疗效，原因是 纤溶酶依赖的补体激活。模型中的初步数据 利用基因缺陷的小鼠中风已经指出了关键的有害作用 通过P-和E-选择素和ICAM-1糖蛋白进行白细胞募集 黏附受体。最近，我们发现脑缺血会触发神经元 表达早期补体成分(C1q，从而潜在地标记 自身进行裂解或受体介导的免疫清除。C1q-表达， 缺血损伤的神经元结合一种可溶性的截短形式的细胞外 补体受体1(SCR1)的结构域，抑制局部补体 激活并对中风患者提供部分脑保护。当这件事 补体抑制蛋白通过SLeX-糖基化共价修饰 此外，抑制选择素介导的事件，观察到显著的收益 减少白细胞和血小板募集，导致安全， 即使延迟治疗，也能提供持久的保护。我们的新数据中的初步数据 再灌流性卒中的灵长类动物模型表现出类似的上调 脑缺血时脑微血管选择素与神经元C1q的表达 区域。在一项针对狒狒中风的双盲安慰剂对照试验中，我们刚刚 完成后，人源化的抗P-/E-选择素抗体显示为中度 脑保护功效。总而言之，这些数据让我们假设 选择素和补体介导的免疫炎症机制有 与中风的病理生理学相关，同时抑制 这两种机制都可能提供一种新的有用的治疗靶点。此外， 鉴于纤溶酶可以激活补体，而抗补体方法可能 对中风尤其有用，可提高疗效和治疗效果 RtPA的窗口。这些数据直接导致了具体的目标，即：(1) 利用C1qa-/-小鼠和C1qA-/-小鼠研究C1q在小鼠卒中中的作用 确定C1q表达的影响是否通过激活 补体的级联和/或通过跨膜和胞浆的局部结合 导致氧化应激和吞噬作用增强的受体；(2)确定 TPA溶栓是否激活补体，从而减少补体 在中风时保护大脑的能力；以及(3)确定 C1q表达在灵长类卒中中的病理生理作用 补体阻断(使用sCR1)策略以及联合抗粘连 受体，抗补体策略(sCR1/SLeX)。

DESCRIPTION (From Applicant's Abstract): Ischemic stroke is a leading cause of death and disability, for which treatment options are very limited. The therapeutic dilemma created by the opposing goals of achieving rapid reperfusion and preventing intracerebral hemorrhage (ICH), has led us to consider the utility of targeting an inflammatory paradigm, the complement cascade, for inhibition in ischemic stroke. Studies are driven by the hypothesis that complement activation contributes directly to cerebral injury in stroke and may indirectly reduce the efficacy of tPA due to plasmin-dependent activation of complement. Preliminary data in a model of stroke using gene deficient mice have pointed to the critical deleterious role for leukocyte recruitment via the P- and E-selectin and ICAM-1 glycoprotein adhesion receptors. More recently, we have shown that ischemia triggers neurons to express an early complement component (C1q, thereby potentially flagging themselves for lysis or receptor mediated immune clearance. C1q-expressing, ischemically injured neurons bind a soluble truncated form of the extracellular domain of the complement receptor 1 (sCR1), which inhibits local complement activation and confers partial cerebral protection in stroke. When this complement-inhibitory protein is covalently modified by sLex- glycosylation to additionally inhibit selectin-mediated events, striking gains are observed in terms of reducing leukocyte and platelet recruitment, leading to a safe, durable protection even with delayed treatment. Preliminary data in our new primate (baboon) model of reperfused stroke demonstrate similar upregulation of cerebral microvascular selectin and neuronal C1q expression in the ischemic zone. In a double-blind placebo-controlled trial of baboon stroke we have just completed, a humanized anti-P-/E-selectin antibody demonstrated moderate cerebral protective efficacy. Together, these data lead us to hypothesize that selectin- and complement-mediated immune-inflammatory mechanisms are pathophysiologically relevant in stroke, and that simultaneous inhibition of both mechanisms may provide a novel and useful therapeutic target. Furthermore, given that plasmin may activate complement, and anti-complement approach might be especially useful in stroke to increase the efficacy of and therapeutic window for rtPA. These data lead directly to the Specific Aims, which are: (1) demonstrate the role of C1q expression in murine stroke using C1qa -/- mice and determine whether the effect of c1q expression is injurious via activation of the complement cascade and/or via local binding of transmembrane and cytosolic receptors leading to enhanced oxidative stress and phagocytosis; (2) determine whether thrombolysis with tPA activates complement, thereby diminishing it's capacity to protect the brain in stroke; and (3) determine the pathophysiological contribution of C1q expression in primate stroke using complement blockade (with sCR1) strategy as well as a combined anti-adhesion receptor, anti-complement strategy (sCR1/SLex).