Molecular mechanisms of Trypanosoma cruzi cardiopathogenesis

克氏锥虫心脏病发病的分子机制

• 批准号: 9269509
• 负责人: Pius N Nde
• 金额: $ 36.38万
• 依托单位: MEHARRY MEDICAL COLLEGE
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-05-05 至 2020-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9269509
• 关键词: Acute; Affect; Antibodies; Binding; Biological Assay; Biology; Blocking Antibodies; Blood; Body Fluids; CX3CR1 gene; Cardiac; Cardiac Myocytes; Cardiac development; Cardiomyopathies; Cell membrane; Cell physiology; Cells; Cessation of life; Chronic; Chronic Disease; Collagen; Complement; Data; Development; Endothelin-1; Erythrocytes; Exhibits; Extracellular Matrix Proteins; Feasibility Studies; Fibroblasts; Fibronectins; Fibrosis; Gene Proteins; Genes; Genetic Transcription; Goals; Growth; Health; Heart; Heart Block; Heart Diseases; Heart failure; Human; Immune; Immunoassay; Immunoblotting; Immunoglobulin G; Immunohistochemistry; Immunologics; Incubated; Individual; Infection; Interleukin-13; Intervention; Kinetics; Leu-Ser-Lys-Leu peptide; MADH2 gene; Measures; Mediating; MicroRNAs; Molecular; Monitor; Morbidity - disease rate; Mus; Myocarditis; N-terminal; Parasites; Parasitic infection; Pathogenesis; Pathology; Pathway interactions; Peptide Signal Sequences; Peptide antibodies; Peptides; Phenotype; Play; Proteomics; RNA Interference; Radiolabeled; Reporting; Research; Resources; Role; Structure; Surface; Testing; Thrombospondin 1; Time; Transcript; Transforming Growth Factor beta; Tropism; Trypanosoma cruzi; United States; Up-Regulation; Vasculitis; Virulence; antibody inhibitor; arm; base; calreticulin; chagasic cardiomyopathy; chemokine; combat; coronary fibrosis; cytokine; design; experimental study; heart cell; in vivo; in vivo imaging; knock-down; macrophage; molecular pathology; mortality; mouse model; neglect; novel; obligate intracellular parasite; overexpression; public health relevance; receptor; response; transcription factor

 DESCRIPTION (provided by applicant): Trypanosoma cruzi is an obligate intracellular parasite that infects blood, heart cells and other cells of the body causing debilitating Chagas heart disease. This chronic disease affects several million individuals around the world, including those in the United States; it causes significant morbidity and mortality, yet remains incurable. The long-term goal of this research is to elucidate the early molecular mechanisms that the parasite uses to make the heart fibrotic, leading to heart failure and death. We have shown that invasive T. cruzi trypomastigotes significantly up-regulate the expression of thrombospondin-1 (TSP-1) to accomplish the process of cellular infection. Knockdown of TSP-1 by RNA interference (RNAi) significantly decreased the infection of heart cells by T. cruzi. We also showed that both TSP-1 and the N-terminal domain of TSP-1 (NTSP) were able to interact specifically with the surface of invasive trypomastigotes. In addition, TSP-1 and NTSP pulled down radiolabeled T. cruzi surface calreticulin (TcCRT) in a mini-proteomic assay, and T. cruzi infection is inhibited when parasites are pre-incubated with an anti-TcCRT antibody. This indicates that the TcCRT-TSP-1 interaction is essential for the process of cellular invasion. We also showed that invasive T. cruzi trypomastigotes regulate the expression of profibrotic genes in heart cells; however the exact mechanism remains unknown. Based on our data, we hypothesize that during cellular infection, the interaction of TcCRT and TSP-1 enhances T. cruzi infectivity and induces a fibro genic response via TGF-β dependent and independent pathways. The objective of this application is to delineate a detailed mechanistic understanding of the early molecular interactions between invasive T. cruzi and heart cells leading to the activation of a pro- fibrotic phenotype. This project is therefore significant because it will characterize the lin between TSP-1 up- regulation, the TcCRT-TSP-1 interaction, which enhances T. cruzi infection, TGF-β activation, and the downstream up-regulation of pro-fibrotic genes and proteins in primary human cardiac myocytes and fibroblasts leading to the development of cardiac fibrosis. Additionally, cardiac macrophages purified from infected mice will be characterized to elucidate the immunological arm of T. cruzi induced cardiomyopathy in the presence and absence of endogenous TSP-1. These studies will fill the gap and advance our mechanistic understanding of one of the significant molecular pathologies occurring during cellular infection by T. cruzi. Understanding the mechanism by which this parasite induces heart disease will pave the way for the development of novel molecular intervention strategies to block cardiac pathology thereby making the findings of high significance in the control of Chagas heart disease.

 描述（由适用提供）：克鲁氏锥虫是一种强制性细胞内寄生虫，感染了血液，心脏细胞和人体的其他细胞，导致chagas心脏病令人衰弱。这种慢性疾病会影响世界各地数百万个人，包括美国的人。它会引起明显的发病率和死亡率，但仍无法治愈。这项研究的长期目标是阐明寄生虫用来使心脏纤维化的早期分子机制，导致心力衰竭和死亡。我们已经表明，侵入性的克鲁齐锥虫t. t. t. t. themospomastigotes显着上调了血小板素-1（TSP-1）的表达，以完成细胞感染的过程。通过RNA干扰（RNAi）敲低TSP-1可显着降低T. cruzi的心脏细胞感染。我们还表明，TSP-1和TSP-1（NTSP）的N末端结构域都能够与浸润性锥虫的表面特别相互作用。此外，TSP-1和NTSP在微型蛋白质分析中拉下了放射性标记的Cruzi表面钙网蛋白（TCCRT），当寄生虫与抗-TCCRT抗体预孵育时，抑制了克鲁兹的感染。这表明TCCRT-TSP-1相互作用对于细胞浸润过程至关重要。我们还表明，侵入性的克鲁氏杆菌锥虫调节心脏细胞中纤维化基因的表达。但是，确切的机制仍然未知。基于我们的数据，我们假设在细胞感染期间，TCCRT和TSP-1的相互作用增强了Cruzi感染，并通过TGF-β依赖性和独立途径诱导纤维遗传反应。该应用的目的是描述对早期的详细机械理解 侵入性T. cruzi和心脏细胞之间的分子相互作用导致促纤维化表型的激活。因此，该项目之所以重要，是因为它将表征TSP-1上调，TCCRT-TSP-1相互作用之间的LIN，从而增强了Cruzi感染，TGF-β激活，TGF-β激活以及对原发性人类心脏肌细胞和纤维细胞中促纤维化基因的下游上调，导致心脏纤维的发育。此外，在存在和不存在内源性TSP-1的情况下，将阐明从感染小鼠纯化的心脏巨噬细胞阐明T. cruzi诱导的心肌病的免疫部门。这些研究将填补空白，并提高我们对Cruzi细胞感染期间发生的重要分子病理之一的机械理解。了解这种寄生虫诱导心脏病的机制将为开发新的分子干预策略铺平道路，以阻止心脏病理学，从而使发现对控制木塔心脏病具有很高的意义。