Complement activation in glaucoma

描述(申请人提供)：我们已经证明了在青光眼视网膜中表达改变的主要基因之一是补体成分C1q。在DBA/2小鼠青光眼模型、激光诱导的猴子青光眼和人类青光眼模型中，视网膜C1q在疾病过程的早期上调。我们还在以DBA/2为背景产生同源C1q基因敲除(KO)菌株方面取得了重大进展，我们将在未来的研究中使用该菌株来了解C1q在青光眼中的作用。C1q和其他补体基因表达的变化，提示神经炎症过程在青光眼视网膜神经节细胞(RGC)病理中起作用。事实上，我们提出的初步证据表明，炎症反应在DBA/2小鼠RGC丢失的发生中起关键作用。在此基础上，结合补体在调节获得性免疫中的作用，提出补体激活参与青光眼发病机制的假说：补体激活的中间成分引起RGC轴突和胞体损伤。[这种损害是否直接或间接发生(通过对支持细胞、视网膜胶质细胞或免疫细胞和细胞外基质的影响)超出了本项目的范围]。为了验证这一假设，我们必须首先了解许多效应器补体分子中的哪些参与了这一过程。因此，我们提出以下特定目标：SA1.检测诱导和自发性(DBA/2)小鼠青光眼模型、激光诱导的灵长类青光眼和青光眼患者的标本中中间补体成分的表达水平和/或数量发生变化的推论。SA2.确定补体激活通过经典途径是否参与了疾病的病理生理学，通过表征我们在前一个资助期产生的同源DBA/2 C1q-/-动物的表型。SA3.确定C4和C3补体成分是否是青光眼病理发展所必需的。这将通过评估同源DBA/2 C4-/-和C3-/-动物以及C4和C3KO以及遭受激光诱导眼压升高的野生动物的RGC和轴突丢失以及神经胶质细胞的激活来实现。SA4.确定C5在青光眼发病机制中是否具有保护作用。这将通过评估DBA/2C5同源基因充足的动物以及C5KO和野生型小鼠的RGC和轴突丢失以及神经胶质细胞的激活来实现。SA5.测定压力对体外培养的Muller细胞和RGC补体成分表达的影响。这项建议将剖析各种补体成分，以便准确确定它们在青光眼发病机制中的作用。这一发现将对其他神经退行性疾病产生更广泛的影响。公共卫生相关性：C1q和其他补体基因表达的变化，表明神经炎症过程在青光眼视网膜神经节细胞(RGC)病理中起作用。尽管一旦发现了涉及神经退行性变的新途径(在这种情况下是抗补体疗法)，就很有可能尝试引入新的疗法，但重要的是首先要充分了解任何干预措施的所有影响，以避免浪费宝贵的资源，甚至潜在地伤害患者。这项建议将剖析各种补体成分，以便准确确定每一种成分在青光眼发病机制中的作用，并使我们能够合理地设计新的治疗方法。

DESCRIPTION (provided by applicant): We have shown that one of the major genes with altered expression in the glaucomatous retina is complement component C1q. Retinal C1q is up-regulated early in the disease process in the DBA/2 mouse model of glaucoma, in laser induced monkey glaucoma and in human glaucoma. We have also made significant progress towards generating a congenic C1q knockout (KO) strain on the DBA/2 background which we will employ in future studies to understand the role of C1q in glaucoma. The changes in expression of C1q and other complement genes, suggest that a neuro-inflammatory process is operational in glaucomatous retinal ganglion cell (RGC) pathology. In fact we present preliminary evidence that an inflammatory reaction is critical for the development of RGC loss in the DBA/2 mouse. Based on the above and the role that complement plays in modulating adaptive immunity we propose the following hypothesis on how complement activation participates in the pathogenesis of glaucoma: Intermediate components of complement activation cause RGC axon and soma damage. [Whether this damage occurs directly or indirectly (through effects on supportive cells, retinal glia or immune cells and extracellular matrix) is beyond the scope of the present project]. To test this hypothesis we must first understand which of the many effector complement molecules are involved in this process. We thus propose the following specific aims: SA1.Test the corollaries that expression levels and/or amounts of intermediate complement components are altered in the retinas from induced and spontaneous (DBA/2) mouse models of glaucoma, as well as in laser induced primate glaucoma and in specimens from patients with glaucoma. SA2. Determine whether complement activation through the classical pathway is involved in the pathophysiology of the disease by characterizing phenotypically the congenic DBA/2 C1q -/- animals we have generated in the previous funding period. SA3. Determine whether the C4 and C3 complement components are required for development of the glaucomatous pathology. This will be achieved by assessing RGC and axonal loss as well as glial activation in congenic DBA/2 C4 -/-and C3-/- animals, as well as in C4 and C3 KO and wild type animals subjected to laser- induced IOP elevation. SA4. Determine whether C5 has a protective role in the pathogenesis of glaucoma. This will be achieved by assessing RGC and axonal loss as well as glial activation in congenic DBA/2 C5 sufficient animals as well as in C5 KOs and wild type mice subjected to laser-induced IOP elevation. SA5. Determine the effect of pressure on Muller cell and RGC complement component expression in vitro. This proposal will dissect the various complement components to allow precise determination of their role in the pathogenesis of glaucoma. Findings will have wider implications for other neurodegenerative disease. PUBLIC HEALTH RELEVANCE: Changes in expression of C1q and other complement genes, suggest that a neuro- inflammatory process is operational in glaucomatous retinal ganglion cell (RGC) pathology. Although it is tempting to try to introduce new therapies once a new pathway involved in neurodegeneration has been identified (in this case anti-complement therapies), it is important to first fully understand all the implications of any intervention in order to avoid wasting valuable resources and potentially even harming patients. This proposal will dissect the various complement components to allow precise determination of the role of each one in the pathogenesis of glaucoma and allow us to rationally design new therapeutic approaches.