Complement dysregulation and atypical hemolytic uremic syndrome

补体失调和非典型溶血性尿毒症综合征

• 批准号: 8996135
• 负责人: Wenchao Song
• 金额: $ 40万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-02-01 至 2020-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8996135
• 关键词: Affinity; Alternative Complement Pathway; Amino Acids; Anemia; Arginine; Autoimmune Process; Binding; Biochemical; C-terminal; Cells; Comparative Study; Complement; Complement 3b; Complement Activation; Complement Factor H; Development; Disease; Engineering; Family; Gene Targeting; Genes; Health; Hemolytic-Uremic Syndrome; Heparin; Host Defense; Human; Injury; Kidney Failure; Knock-in Mouse; Lead; Light; Link; Mediating; Mediator of activation protein; Mus; Mutant Strains Mice; Mutation; Natural Immunity; Neurologic; Pathogenesis; Pathology; Pathway interactions; Patients; Pharmaceutical Preparations; Phenotype; Plasma; Play; Positioning Attribute; Role; Stroke; Symptoms; Testing; Therapeutic; Tissues; Tryptophan; arm; complement system; disease phenotype; human disease; in vivo; kidney vascular structure; mouse model; prevent; vascular abnormality

 DESCRIPTION (provided by applicant): The complement system is an important arm of innate immunity that plays a key role in host defense. However, activated complement also has the potential to cause autoimmune injury, and accordingly its activation in vivo must be carefully controlled. Several cell-anchored and plasma complement regulators exist to protect host tissues from complement injury. Mutations in such complement regulators can lead to abnormal levels of alternative pathway complement activation and result in complement-mediated pathology. Recent studies have linked mutations in the plasma complement regulator factor H (FH) to atypical hemolytic uremic syndrome (aHUS), but the mechanisms by which FH mutations cause complement dysregulation which in turn leads to the various described symptoms of human aHUS are still poorly understood. The focus of this proposal is to generate and use mouse models of aHUS by introducing FH mutations through gene targeting to understand the mechanism of alternative pathway complement dysregulation and aHUS pathogenesis. In preliminary studies, we have engineered a FH knock-in mouse whereby we substituted the amino acid Tryptophan (W) at position 1183 located in the C-terminal domain of FH with an Arginine (R). The W1183R change is a well-recognized mutation in human FH found in multiple families of aHUS patients and mice carrying homozygous W1183R mutation developed severe aHUS. Our specific aims are: 1) to further characterize the aHUS phenotype and associated pathologies including neurological, renal and vascular abnormalities in the FH W1183R mutant mice; 2) to define the specific role of complement component(s) and mediator(s) in the pathogenesis of aHUS and associated pathologies and test if blocking such components or mediators can prevent or reverse the disease phenotypes; 3) To generate a second FH mutant mouse by introducing an R1215G mutation in FH and compare its phenotype with that of W1183R mutant mice. Both the W1183R and R1215G mutations are found in human aHUS patients, yet biochemical studies have shown that these mutations caused opposite changes in the binding affinity of FH to C3b and heparin. Comparative studies of the in vivo consequences of these mutations in mice will shed light on this dichotomy. Collectively, the proposed studies will help us understand how FH mutations cause alternative pathway complement dysregulation leading to aHUS and facilitate translational therapeutics of this disorder as well as other complement-mediated diseases.

 描述（由申请人提供）：补体系统是先天免疫的一个重要分支，在宿主防御中起关键作用。然而，活化的补体也有可能导致自身免疫损伤，因此必须小心控制其体内活化。存在几种细胞锚定和血浆补体调节剂以保护宿主组织免受补体损伤。此类补体调节因子的突变可导致旁路途径补体激活的异常水平，并导致补体介导的病理学。最近的研究已经将血浆补体调节因子H（FH）中的突变与非典型溶血性尿毒综合征（阿胡斯）联系起来，但是FH突变引起补体失调的机制仍然知之甚少，补体失调进而导致人类阿胡斯的各种所述症状。该提案的重点是通过基因靶向引入FH突变来产生和使用阿胡斯的小鼠模型，以了解旁路途径补体失调和阿胡斯发病机制的机制。在初步研究中，我们已经工程化了FH敲入小鼠，由此我们用精氨酸（R）取代了位于FH的C-末端结构域中的位置1183处的氨基酸色氨酸（W）。W1183 R变化是在多个阿胡斯患者家族中发现的人FH中的公认突变，并且携带纯合W1183 R突变的小鼠发展为严重的阿胡斯。我们的具体目标是：1）进一步表征FH W1183 R突变小鼠中的阿胡斯表型和相关病理，包括神经、肾和血管异常; 2）定义补体组分和介质在阿胡斯和相关病理的发病机理中的特定作用，并测试阻断这些组分或介质是否可以预防或逆转疾病表型; 3）通过在FH中引入R1215 G突变产生第二FH突变小鼠，并将其表型与W1183 R突变小鼠的表型进行比较。W1183 R和R1215 G突变都在人阿胡斯患者中发现，但生物化学研究表明，这些突变导致FH与C3 b和肝素的结合亲和力发生相反的变化。这些突变在小鼠体内后果的比较研究将阐明这种二分法。总的来说，拟议的研究将帮助我们了解FH突变如何导致替代途径补体失调导致阿胡斯，并促进这种疾病以及其他补体介导的疾病的翻译治疗。