Metaorganismal TMAO pathway driving scleroderma pathogenesis: novel gene-environment interaction paradigm and therapeutic target

项目总结/摘要 系统性硬化症（SSc）是一种典型的纤维化疾病，几乎影响到每个器官。遗传和环境 这两种因素都会导致疾病。除了纤维化，血管损伤和肠道生态失调是突出的; 然而，这些不同的过程是如何由基因-环境相互作用控制的，以及它们是如何联系在一起的， 在发病机理上的共同作用在很大程度上是未知的，排除了疾病改善疗法的发展。基于 从我们实验室和其他实验室获得的最新数据来看，我们现在提出了一个难以捉摸的基因的新范式- SSc中的环境相互作用，将肠道微生物代谢与血管损伤和纤维化联系起来， 创新疗法的大门：1）暴露于西方饮食的肠道微生物群产生三甲胺（TMA）， 在宿主体内通过含黄素的单加氧酶转化为三甲胺N-氧化物（TMAO） （FMO3）。升高的TMAO与内皮细胞损伤、促进纤维化细胞表型和 组织纤维化; 2）FMO 3的遗传变异体显示与SSc高度显著相关;以及3）FMO 3的表达， FMO 3在SSc皮肤成纤维细胞中显著上调。我们的假设是，富含胆碱的饮食通过 代谢轴产生升高的TMAO，其通过代谢促进血管损伤和器官纤维化。 内皮-间充质转化（endoMT）和其他参与SSc发病机制的途径。我们提出 纤维化倾向可以通过选择性抑制肠道TMA裂解酶（微生物酶）来减轻， 专门负责TMA生成。这代表了一种独特的和变革性的治疗模式。 在最初的两年（R61阶段），我们将确定饮食依赖性慢性TMAO升高是否以及如何 影响不同体内疾病模型和凋亡细胞中的纤维化。我们将评估是否有必要- 选择性抑制肠道中TMA裂解酶的相关新化合物改变了这些反应。我们将 确定endoMT是否代表了饮食相关TMAO升高和血管紧张素转换酶（VEGF） 损伤和纤维化。在第3年（R33阶段），在实现我们预定义的里程碑后，我们将定义 FMO 3在饮食诱导纤维化倾向中的作用，并确定循环TMAO是否是潜在的诊断 SSc及其内型的横截面和纵向研究的预后生物标志物。这个项目 旨在验证一种全新的SSc范式，该范式将环境/饮食和遗传风险（FMO 3变体）联系起来 在作为SSc发病机制基础的代谢途径中，可以选择性地靶向治疗。

PROJECT SUMMARY/ABSTRACT Systemic sclerosis (SSc) is a prototypic fibrotic illness affecting virtually every organ. Genetic and environmental factors both contribute to disease. In addition to fibrosis, vascular injury and gut dysbiosis are prominent; however, how these distinct processes are governed by gene-environment interactions, and how they are linked together in pathogenesis is largely unknown, precluding development of disease-modifying therapy. Based on remarkable recent data from our lab and others, we now propose a novel paradigm for the elusive gene- environment interaction in SSc that ties gut microbial metabolism to vascular injury and fibrosis and opens the door for innovative therapy: 1) gut microbiota exposed to a Western diet generate trimethylamine (TMA), which is converted in the host to trimethylamine N-oxide (TMAO) by the enzyme flavin-containing monooxygenase (FMO3). Elevated TMAO is associated with endothelial cell injury, promotion of fibrotic cellular phenotypes, and tissue fibrosis; 2) genetic variants of FMO3 show highly significant association with SSc; and 3) expression of FMO3 is significantly upregulated in SSc skin fibroblasts. Our hypothesis is that choline-rich diets via a metaorganismal axis generate elevated TMAO, which promotes vascular injury and organ fibrosis via endothelial-mesenchymal transition (endoMT) and other pathways implicated in SSc pathogenesis. We propose that the fibrotic propensity can be mitigated by selectively inhibiting gut TMA lyase, the microbial enzyme exclusively responsible for TMA generation. This represents a distinct and transformative treatment paradigm. During the first two years (R61 phase), we will determine if and how diet-dependent chronic TMAO elevation impacts fibrosis in distinct in vivo disease models and explanted cells. We will then evaluate if a translationally- relevant novel compound that selectively inhibits TMA lyase in the gut modifies these responses. We will determine whether endoMT represents a key mechanism linking diet-associated TMAO elevation and vascular injury and fibrosis. In Year 3 (R33 phase), undertaken upon achieving our predefined milestones, we will define the role of FMO3 in diet-induced fibrosis propensity, and determine if circulating TMAO is a potential diagnostic and prognostic biomarker of SSc and its endotypes in both cross-sectional and longitudinal studies. This project seeks to validate an entirely novel SSc paradigm that links the environment/diet and genetic risk (FMO3 variants) in a metaorganismal pathway that underlies SSc pathogenesis and can be selectively targeted for therapy.