Aryl Hydrocarbon Receptor Ligands and Thyroid Eye Disease

描述（由申请人提供）：芳烃受体（AhR）是一种配体激活的转录因子，可结合多种合成和天然化合物。我们最近发现，用AhR配体治疗人眼眶成纤维细胞不仅会损害tgfb驱动的肌成纤维细胞的形成，还会抑制gpi锚定蛋白Thy1的表达。这一发现很重要，因为人眼眶成纤维细胞是异质的，可以根据其表面Thy1的表达分为两个亚群。与缺乏Thy1的细胞不同，表达Thy1 （Thy1+）的眼眶成纤维细胞具有形成肌成纤维细胞的潜力。激活的眼眶成纤维细胞转化为产生瘢痕的肌成纤维细胞是甲状腺眼病（TED）威胁视力和无法治愈的关键病理特征。肌成纤维细胞产生过量的α -平滑肌肌动蛋白、胶原蛋白和透明质酸，导致眼眶僵硬、纤维化。超过一半的格雷夫斯病患者会发生TED。慢性眼窝炎症导致广泛的组织重塑，引起疼痛、眼球突出，甚至失明。目前对TED的治疗方法，如皮质类固醇、外部束辐射和手术，针对的是疾病的后果，而不是病因，并导致不必要的副作用，包括手术后的发病率。我们的长期目标是了解TED背后的机制，从而导致基于机制的治疗。由于没有很好的TED动物模型，我们的转化研究使用原发的人类轨道成纤维细胞来准确地再现TED轨道上的事件。鉴定抑制TED肌成纤维细胞的分子是迫切需要的，而AhR配体（如ITE， FICZ）是一类有潜力用于TED的小分子。目的：确定AhR配体在TED中减轻肌成纤维细胞形成和细胞外基质积累的治疗价值和基本机制。我们还将发现AhR配体抑制Thy1表达的潜在机制，并确定AhR配体的抗疤痕特性是否需要抑制Thy1。组织假说：AhR配体在TED中减弱人眼眶肌成纤维细胞的产生和结缔组织重塑。具体目的1：验证关键小分子AhR配体阻断人眼眶成纤维细胞向肌成纤维细胞分化的预测。具体目标2：确定AhR配体阻断人眼眶成纤维细胞向肌成纤维细胞分化的机制。特异性目的3：研究AhR配体如何通过调节Thy1表达介导眼眶肌成纤维细胞的形成。意义：发现AhR配体在治疗TED中具有治疗价值是一项重大进展，为TED治疗建立了新的候选药物和靶点。我们将确定TED中Thy1表达、肌成纤维细胞形成和细胞外基质积累的机制，并将这些知识转化为临床相关的创新方法，以减轻甚至治愈TED中的眼眶重塑和瘢痕形成。

DESCRIPTION (provided by applicant): The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that binds diverse synthetic and natural compounds. We recently discovered that treating human orbital fibroblasts with AhR ligands not only impairs TGFb-driven myofibroblast formation, but also inhibits expression of the GPI-anchored protein, Thy1. This finding is important because human orbital fibroblasts are heterogeneous and can be divided into two subsets based on their surface expression of Thy1. Orbital fibroblasts expressing Thy1 (Thy1+) have the potential to form myofibroblasts, unlike cells lacking Thy1. And, the conversion of activated orbital fibroblasts to form scar-producing myofibroblasts is a key sight-threatening and incurable pathological feature of Thyroid Eye Disease (TED). Myofibroblasts produce excessive amounts of alpha-smooth muscle actin, collagen and hyaluronan leading to a stiff, fibrotic orbit. TED occurs in more than half of patients with Graves' Disease. Chronic orbital inflammation in TED leads to extensive tissue remodeling causing pain, proptosis, and even blindness. Current treatments for TED such as corticosteroids, external beam radiation and surgery are aimed at the consequences of disease, rather than the etiology, and cause unwanted side effects including post-surgical morbidity. Our long-term goal is to understand the mechanisms underlying TED leading to mechanism-based therapies. As there is no good animal model of TED, our translational studies use primary human orbital fibroblasts that accurately reproduce the events in the TED orbit. Identification of molecules that blunt TED myofibroblasts is a pressing need, and AhR ligands (e.g. ITE, FICZ) are a promising class of small molecules for potential use in TED. Goals: Establish the therapeutic value and the fundamental mechanisms whereby AhR ligands attenuate myofibroblast formation and extracellular matrix accumulation in TED. We will also discover the underlying mechanisms whereby AhR ligands repress Thy1 expression and determine if Thy1 repression is required for the anti-scarring properties of AhR ligands. Organizing Hypothesis: AhR ligands attenuate human orbital myofibroblast production and connective tissue remodeling in TED. Specific Aim 1: Test the prediction that key small molecule AhR ligands block human orbital fibroblast-to-myofibroblast differentiation. Specific Aim 2: Determine the mechanisms whereby AhR ligands block human orbital fibroblast-to-myofibroblast differentiation. Specific Aim 3: Investigate how AhR ligands mediate orbital myofibroblast formation by regulating Thy1 expression. Significance: Discovering that AhR ligands have therapeutic value in treating TED is a major advance, establishing new candidate drugs and targets for TED therapies. We will identify the mechanisms underlying Thy1 expression, myofibroblast formation and extracellular matrix accumulation in TED, and translate this knowledge into clinically relevant and innovative approaches to attenuate or even cure orbital remodeling and scarring in TED.