Genetic Determinants of Chagas Cardiomyopathy

摘要 慢性恰加斯病心肌病（CCC）是心力衰竭的主要感染原因。CCC出现在20- 30%的患者感染了克氏锥虫，这是一种在拉丁美洲流行的寄生虫。流行病学 研究表明，超过700万拉丁美洲人感染了T。cruzi，包括美国约30万移民。 感染是通过昆虫媒介、受感染的献血者和受感染的孕妇传播的 将寄生虫传给新生儿CCC出现后数年或数十年后，静止发展的进行性 心室扩张伴收缩功能下降、传导系统疾病和心律失常。CCC 是一种被忽视的疾病，没有有效的治疗方法， 移植后，大多数CCC过早死亡。此外，T.据预测， 增加CCC的发病率。 这项建议旨在确定遗传和免疫因素，促进CCC和阐明如何T。cruzi 损害心脏。我们的研究将利用与A博士的合作。佩雷拉和巴西人 恰加斯病心肌病遗传学联盟已经积累了临床数据、生物标本和 来自> 3，000名受试者的CCC心脏。通过这一广泛修订的应用程序，我们纳入了新的 激发拟议实验的候选宿主和寄生虫基因的初步结果。我们的研究 将开发新的试剂，包括新构建和验证的捕获试剂来测序T。cruzi 来自培养物、血液和分离的CCC心脏的外显子组，以鉴定富集在 CCC.我们提出了创新的方法来评估CCC发展中的宿主免疫反应， 全面的血清学分析，以确定T。患者体内宿主抗体识别的Cruzi表位 有和没有CCC我们将确定这些抗体是否与心脏蛋白交叉反应。我们还将 研究可能通过干扰iPS细胞来源的基因表达来促进发病机制的候选基因 心肌细胞和成纤维细胞以及感染小鼠的体内分析。通过对成纤维细胞的平行研究 和心肌细胞，我们将测试是否细胞特异性反应T。Cruzi为CCC做出了贡献。此外，我们将 确定T. Cruzi诱变导致了对杀Parricidal剂的抗性。 总之，这些研究应该促进新的基本知识的机制，T。 克氏感染扰乱心脏形态和功能并引起CCC。我们的目标是： 1)识别人类和寄生虫中调节对T. cruzi 感染和促进CCC; 2）鉴定和比较CCC病例和对照的宿主抗体。 cruzi表位与心脏蛋白的关系; 3）比较CCC组织、T. cruzi感染的iPS-CM、遗传性和缺血性心肌病以及未受影响的供体心脏;以及4） 分析细胞和小鼠模型，探索促进CCC的宿主-病原体相互作用。

ABSTRACT Chronic Chagas cardiomyopathy (CCC) is a leading infectious cause of heart failure. CCC emerges in 20- 30% of patients infected with Trypanosoma cruzi, a parasite that is endemic in Latin America. Epidemiologic studies indicate over 7 million Latinos are infected with T. cruzi, including ~300,000 immigrants in the U.S. Infection is transmitted by insect vectors, infected blood donors, and infected pregnant women who transmit the parasite to newborns. CCC emerges after years or decades after quiescent development of progressive ventricular dilatation with diminished systolic performance, conduction system diseases and arrhythmias. CCC is a neglected disease for which there are no effective treatments and due to limited access to cardiac transplantation, most CCC die prematurely. Moreover, the growing burden of T. cruzi infection is predicted to increase the incidence of CCC. This proposal seeks to identify genetic and immune factors that promote CCC and to elucidate how T. cruzi damages the heart. Our studies will capitalize on a collaboration with Dr. A. Pereira and the Brazilian Consortium for Genetics of Chagas Cardiomyopathy, which has amassed clinical data, bio-specimens and explanted CCC hearts from >3,000 subjects. With this extensively revised application we incorporate new Preliminary Results on candidate host and parasite genes that motivate the proposed experiments. Our studies will exploit novel reagents, including a newly constructed and validated capture reagent to sequence T. cruzi exomes from culture, blood and explanted CCC hearts, to identify parasite genetic variants that are enriched in CCC. We propose innovative approaches to assess host immune response in the development of CCC, by comprehensive serologic profiling to identify T. cruzi epitopes that are recognized by host antibodies in patients with and without CCC. We will determine if these antibodies cross react with cardiac proteins. We will also study candidate genes that may promote pathogenesis by perturbing gene expression in iPS cell derived cardiomyocytes and fibroblasts and by in vivo analyses of infected mice. Through parallel studies of fibroblasts and cardiomyocytes we will test if cell-specific responses to T. cruzi contribute to CCC. In addition, we will determine if T. cruzi mutagenesis accounts for resistance to parricidal agents. Together these studies should promote new fundamental knowledge about the mechanisms by which T. cruzi infection perturbs cardiac morphology and function and causes CCC. We aim to: 1) Identify rare genetic variants in humans and parasites that modulate responses to T. cruzi infection and promote CCC; 2) Identify and compare host antibodies in CCC cases and controls to T. cruzi epitopes and cardiac proteins; 3) Compare cardiac transcriptomes in explanted CCC tissues, T. cruzi-infected iPS-CM, genetic and ischemic cardiomyopathies, and unaffected donor hearts; and 4) Analyze cell and mouse models to explore host-pathogen interactions that promote CCC.