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（申请人提供）：补体系统是先天免疫的重要组成部分，在宿主防御中发挥关键作用，然而，激活的补体也有可能引起自身免疫损伤，因此必须仔细控制其在体内的激活。一些细胞锚定和血浆补体调节剂的存在可以保护宿主组织免受补体损伤，这些补体调节剂的突变可能导致旁路补体激活水平异常，并导致补体介导的病理学。 H因子(FH) 到非典型溶血性尿毒症综合征 (aHUS)，但 FH 突变导致补体失调进而导致人类 aHUS 的各种描述的症状的机制仍然知之甚少。该提案的重点是生成和使用小鼠。通过基因靶向引入 FH 突变来构建 aHUS 模型，以了解替代途径补体失调的机制和 aHUS 发病机制。色氨酸 (W) 位于 FH C 末端结构域中，带有精氨酸 (R)。 W1183R 变化是人类 FH 中公认的突变，在多个 aHUS 患者家族中发现，并且携带纯合 W1183R 突变的小鼠出现严重的突变。 aHUS。我们的具体目标是：1) 进一步表征 aHUS 表型和相关病理学，包括 FH 中的神经、肾脏和血管异常。 W1183R 突变小鼠；2) 确定补体成分和介质在 aHUS 发病机制和相关病理中的具体作用，并测试阻断这些成分或介质是否可以预防或逆转疾病表型；通过在 FH 中引入 R1215G 突变，将其表型与 W1183R 突变小鼠的表型进行比较，W1183R 和 R1215G 突变均在 FH 中发现。人类 aHUS 患者，但生化研究表明，这些突变导致 FH 与 C3b 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的后果的比较研究将阐明这种二分法。将帮助我们了解 FH 突变如何导致替代途径补体失调导致 aHUS，并促进这种疾病以及其他补体介导的疾病的转化治疗。