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: 9198481
• 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/9198481
• 关键词: Affinity; Alternative Complement Pathway; Amino Acid Substitution; 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; 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; 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; public health relevance; 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（由适用提供）：完成系统是先天免疫组织化学的重要部门，在宿主防御中起着关键作用。但是，激活的补体也有可能引起自身免疫性损伤，因此，必须仔细控制其在体内的激活。存在几个细胞锚定和血浆补体调节剂，以保护宿主组织免受完成损伤。这种补体调节剂中的突变会导致替代途径完成激活的异常水平，并导致完成介导的病理。最近的研究已将血浆补体调节因子H（FH）中的突变与非典型溶血性尿毒症综合征（AHUS）联系起来，但是FH突变导致完成功能障碍的机制又导致了人类AHU的各种描述的症状，但仍知之甚少。该提案的重点是通过基因靶向引入FH突变来生成和使用小鼠模型，以了解替代途径完成功能障碍和Ahus发病机理的机制。在初步研究中，我们设计了一只FH敲入小鼠，从而在位于FH的C末端域的位置1183的位置提交了氨基酸色氨酸（W），并用精氨酸（R）提交了氨基酸色氨酸（W）。 W1183R的变化是在多个鹰嘴症患者家族和携带纯合W1183R突变的小鼠中发现的人类FH的公认突变。我们的具体目的是：1）进一步表征FH W1183R突变小鼠中神经，肾脏和血管异常，包括神经，肾脏和血管异常的相关病理； 2）定义理解成分和介体在AHU和相关病理的发病机理中的具体作用，并测试阻断此类成分或介体是否可以防止或逆转疾病表型； 3）通过在FH中引入R1215G突变来产生第二个FH突变小鼠，并将其表型与W1183R突变小鼠的表型进行比较。 W1183R和R1215G突变都在人类AHUS患者中发现，但是生化研究表明，这些突变导致FH与C3B和肝素的结合亲和力相反。这些突变在小鼠中的体内后果的比较研究将揭示这种二分法。总的来说，拟议的研究将有助于我们了解FH突变如何引起替代途径的完成失调，从而导致痤疮并促进该疾病的转化治疗以及其他完成介导的疾病。