Building a Better AMD Mouse

描述(申请人提供)：年龄相关性黄斑变性(AMD)是一种复杂的疾病，其中许多遗传和环境因素的贡献是混淆的。没有单一的危险因素可以可靠地预测人类的AMD，同样，在动物身上的任何单一干预也不能产生可靠的AMD模型。该病表现为更常见的干型，较不常见的湿型，但更具破坏性。在干性AMD的已提出的机制中，大多数证据表明系统性补体激活失调，主要是由于补体因子H或CFH的多态性和心血管风险特征。最近发现HTRA丝氨酸多肽酶1(HTRA1)是湿性AMD的危险因素，提示湿性AMD存在完全不同的机制(基质代谢异常和转化生长因子-2信号)。这项建议的最终目的是在小鼠身上创造一种早期发病的、全面的AMD眼部表型，以便将来用于治疗试验。我们的中心假设是，结合遗传和环境风险因素可以在小鼠中诱导更全面的AMD样病理。首先，我们将验证补体失调和脂质诱导的全身性炎症相结合可以加重AMD样病理的假设。在目标1中，我们将在人类(CFH)或小鼠(ApoE，CCR2)中培育缺乏一个或多个AMD风险基因的小鼠，并将这些小鼠暴露在正常或高脂肪高胆固醇饮食中。将比较基因和饮食对眼部病理和炎症生物标志物发展的影响。接下来，我们将探讨HTRA1过表达在湿性AMD中的作用。在目标2中，我们将产生一种Cre-Lox可诱导的HTRA1敲击小鼠，它在a)内皮细胞或b)大多数组织中过表达人HTRA1。这一目标将检验HTRA1过度表达可以诱导湿性AMD典型的脉络膜新生血管的假说。AIM 1中的实验将深入了解，当与额外的遗传和饮食风险因素结合时，完全CFH/-缺失是否会导致类似AMD的病理。在目标2中，我们将彻底检验HTRA1表达增加促进CNV的假设。这项研究的长期目标是结合Aim1和Aim2中开发的模型，在人类中提供一个全面的进行性(即从干到湿)AMD的小鼠模型。老年性黄斑变性是65岁以上成年人视力丧失的主要原因。缺乏有效的治疗方法既源于疾病的复杂性，也源于缺乏良好的动物模型来研究它。这一提议提供了一种用于治疗测试的健壮的早期发病小鼠模型。这些实验还提供了对可修改变量(饮食)如何与易患遗传负担相互作用创建AMD病理的洞察。了解这些关系将增强临床医生咨询高危患者的能力。

DESCRIPTION (provided by applicant): Age-related macular degeneration (AMD) is a complex disease in which the contributions of many genetic and environmental factors are confounding. No single risk factor can predict AMD reliably in humans, and similarly, no single intervention in animals is able to produce a robust AMD model. The disease manifests as the more common dry form, and the less common, but more devastating wet form. Of the proposed mechanisms for dry AMD, most evidence exists for dysregulated systemic complement activation, predominantly due to polymorphisms in complement factor H, or CFH and a cardiovascular risk profile. The recent discovery of a polymorphic variant of HTRA Serine Peptidase 1 (HTRA1) as a risk factor for wet AMD implicates an entirely different mechanism (abnormal matrix metabolism and TGF-2 signaling) underlying the wet form of AMD. The ultimate intent of this proposal is to create an early onset, comprehensive AMD ocular phenotype in mice for future use in therapeutic trials. Our central hypothesis is that combining genetic and environmental risk factors can induce more comprehensive AMD-like pathology in mice. First, we will test the hypothesis that combined complement dysregulation and lipid-induced systemic inflammation can worsen AMD-like pathology. In Aim 1, we will breed mice lacking one or more genes conferring AMD risk in humans (CFH) or mice (ApoE, Ccr2) and expose these to normal or high fat high cholesterol diets. The effects of genotype and diet upon development of ocular pathology and biomarkers of inflammation will be compared. Next, we will explore the role of HTRA1 overexpression in wet AMD. In Aim 2, we will generate a Cre-Lox inducible HTRA1 knockin mouse that overexpresses human HTRA1 in a) endothelium or b) in the majority of tissues. This aim will test the hypothesis that HTRA1 overexpression can induce choroidal neovascularization typical of wet AMD. Experiments in Aim 1 will provide insight into whether complete CFH-/- deletion can result in AMD-like pathology when combined with additional genetic and dietary risk factors. In Aim 2, we will thoroughly test the hypothesis that increased expression of HTRA1 promotes CNV. The long term goal of this study is to combine the models developed in Aim1 and 2 to provide a comprehensive mouse model of progressive (i.e dry to wet) AMD in humans. Age-related macular degeneration is the predominant cause of vision loss in adults over 65. Lack of effective treatment stems from both the complexity of the disease, and lack of good animal models in which to study it. This proposal offers the potential to provide a robust early onset mouse model for therapeutic testing. These experiments also provide insight into how modifiable variables (diet) interact with predisposing genetic burden to create AMD pathology. Understanding these relationships will enhance the capacity of the clinician to council at-risk patients.