Genesis and Progression of Cerebral Cavernous Malformations

脑海绵状血管瘤的发生和进展

基本信息

批准号：
7642968
负责人：
ISSAM A AWAD
金额：
$ 48.46万
依托单位：
DUKE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-05-01 至 2013-02-28
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7642968
关键词：
Age Alleles American Anatomy Animal Model Animals Appearance Basement membrane Biologically Based Therapy Blood - brain barrier anatomy Blood Vessels Blood capillaries Brain CCM1 gene Categories Cavernous Hemangioma Cavernous Malformation Cell Line Cell Proliferation Cells Cellular Structures Cerebrum Characteristics Classification Classification Scheme Clinical Collection Complex Control Animal Cutaneous DNA Sequence Detection Development Dissection Electron Microscopy Endothelial Cells Epigenetic Process Event Exhibits Foot Process Future Gene Mutation Generations Genes Genetic Genetic Research Germ-Line Mutation Goals Growth Hemangioma Hemorrhage Heterozygote Human Image Inherited Intercellular Junctions Investigation Iron Knock-out Laminin Lasers Lead Lesion Lesion by Stage Light Link Magnetic Resonance Imaging Methodology Mismatch Repair Modeling Modification Molecular Molecular Analysis Mus Mutagenesis Mutation Nature Neoplasms in Vascular Tissue Neuroglia Neurologic Operative Surgical Procedures Pathogenesis Pathology Patient Selection Patients Pericytes Phase Phenotype Point Mutation Prevalence Prevention Process Proliferating Proteins Public Health Reporting Research Resected Resolution Retinoblastoma Risk Role Sampling Screening procedure Seizures Selection Bias Smooth Muscle Actin Staining Method Somatic Mutation Staging Staining method Stains Stroke Suggestion Surveys System TP53 gene Techniques Testing Tight Junctions Time Tissues Translating Tumor Suppressor Genes Tumor Suppressor Proteins Vascular Endothelial Cell Vascular Proliferation Vascular remodeling Work autosomal dominant trait capillary clinically relevant design human disease indexing lifetime risk malformation man meetings mouse model mutant neurovascular unit novel novel strategies public health relevance therapeutic target

项目摘要

DESCRIPTION (provided by applicant): More than one million Americans harbor cerebral cavernous malformations (CCMs), consisting of clusters of proliferating dilated hemorrhagic capillaries, predisposing patients to a lifetime risk of stroke, seizures, and other neurologic sequelae. CCMs can develop sporadically, but the risk to develop CCMs can also be inherited by mutation in one of three recently identified genes. The presence of solitary lesions in sporadic cases and multiple, randomly-scattered lesions in autosomal dominant cases have led us to hypothesize that CCM lesion genesis follows a Knudson two-hit mechanism requiring somatic loss of the wild-type allele, leading to endothelial cell proliferation and CCM growth. We can test our hypothesis by analyzing human CCM lesion tissue for the presence of bi-allelic mutations in the respective CCM gene. Unfortunately, the assessment of somatic mutations and proliferative activity at earliest stages of lesion development in humans is hindered by a strong selection bias in tissue availability. Smaller CCMs, especially at earliest phases of lesion genesis, are rarely if ever surgically resected. Thus, we cannot determine whether bi-allelic mutations identified in the human lesions are the cause or merely an effect of lesion growth. In order to test our two-hit hypothesis for lesion genesis, we have created mouse models with targeted mutations of either Ccm1 or Ccm2, where heterozygote animals develop CCM lesions only in a genetic background null for the tumor suppressor Trp53 (p53) gene. We are concurrently developing second generation models, where the Ccm genes are similarly crossed into a genetic background deficient in mismatch repair, in order to bias somatic mutations towards simple point mutations easily identified by DNA sequencing. We have in parallel developed high resolution magnetic resonance (MR) imaging and stereotactic localization techniques which enable the detection and characterization of murine lesions, and cellular dissection from lesions at earliest stages of development. Using this novel platform and a collection of banked excised human lesions, we propose three specific aims investigating the following hypotheses: (1) that somatic mutation in the wild type copy of the appropriate Ccm gene occurs at early (dilated capillary) stage of lesion genesis, and is expanded clonally in cavernous vessels of later stage (multi-cavernous) CCM lesions in mice with targeted mutagenesis; (2) that lesions develop and grow over time, and endothelial cells in both early and late stage murine CCM lesions exhibit proliferative activity and alterations of the blood-brain-barrier; and (3) that somatic mutations in resected human CCM lesions validate the two-hit mechanisms of lesion genesis in man. This work will shed light on the molecular mechanism of CCM genesis, and aid in our long term goal of finding new approaches to their prevention and treatment. PUBLIC HEALTH RELEVANCE: The relevance of this research to public health is that in this study we will investigate hypotheses that CCM lesions develop and grow over time, and that they are associated with a classic two-hit tumor suppressor mechanism leading to proliferation of vascular tissue with a defective blood brain barrier, leading to subsequent hemorrhage and associated neurological sequelae. Answers to these questions will allow the proper classification of these clinically important lesions and lead to future investigation down the appropriate path for development of biologically-based therapy.

描述（由申请人提供）：超过一百万的美国人藏有脑海绵状畸形（CCMS），由扩散的扩张的出血毛细血管群组成，使患者容易患有中风，癫痫发作，癫痫发作和其他神经学序列。 CCM可以偶尔发展，但是开发CCM的风险也可以通过突变遗传到最近确定的三个基因之一中。常染色体显性病例中零星病变和多个随机裂痕病变的存在使我们假设CCM病变的发生是knudson the thiT的两次打击机制，需要躯体损失野生型等位基因，导致内皮细胞扩散和CCM的生长。我们可以通过分析人类CCM病变组织中是否存在相应的CCM基因中存在双性突变来检验我们的假设。不幸的是，在组织可用性中的强烈选择偏见阻碍了人类病变发育最早的体细胞突变和增生活性的评估。较小的CCM，尤其是在病变发生的最早阶段，很少是手术切除的。因此，我们无法确定在人病变中鉴定出的双行性突变是原因还是仅仅是病变生长的作用。为了测试我们的两次损害生成的假设，我们创建了具有CCM1或CCM2的靶向突变的小鼠模型，其中杂合子动物仅在肿瘤抑制TRP53（p53）基因的遗传背景中仅在遗传背景中出现CCM病变。我们正在同时开发第二代模型，其中类似地将CCM基因跨成缺乏不匹配修复的遗传背景，以使体细胞突变偏向DNA测序轻松识别的简单点突变。我们在并行发展了高分辨率磁共振（MR）成像和立体定位技术，从而使鼠病变的检测和表征能够在最早发育阶段进行病变的细胞解剖。使用这个新型平台和一系列融合的人病变，我们提出了三个具体目的，研究以下假设：（1）适当CCM基因的野生型副本中的体突变发生在病变创世记的早期（扩张毛细血管）阶段，并在后期阶段（以后的阶段）（跨阶段）的CCM lise ccm les ccm les ccm ccm les ccm insepers expection; （2）随着时间的流逝，病变发展和生长，早期和晚期的鼠CCM病变中的内皮细胞表现出增殖活性和血脑屏障的改变；（3）切除的人CCM病变中的体细胞突变验证了人类病变发生的两次打击机制。这项工作将阐明CCM Genesis的分子机制，并有助于我们长期目标，即寻找新的预防和治疗方法。公共卫生相关性：这项研究与公共卫生的相关性是，在这项研究中，我们将调查CCM病变随着时间的流逝而发展和生长的假设，并且它们与经典的两次肿瘤抑制机制相关，导致血管组织增殖，并具有有缺陷的血液脑屏障，导致随后的血液障碍和相关的神经系统sequelae。这些问题的答案将允许对这些临床上重要的病变进行适当的分类，并导致未来研究基于生物学的治疗的适当途径。