TNF family members for lymph angiogenesis and lymph node hypertrophy

描述（由申请人提供）：外周组织中淋巴血管（LV）和高内皮小静脉（HEV）的快速发展导致炎症/疫苗接种期间引流淋巴结（LN）肥大，但调节LN肥大的分子机制尚不清楚。淋巴毒素（LT）、肿瘤坏死因子、肥大细胞和树突状细胞都参与了疫苗接种后或炎症期间LN肥大的调节。出乎意料但有趣的是，我们的初步研究揭示了与LT共享LT2R受体的LIGHT （TNFRSF14）也是LN肥大所必需的，因为LIGHT KO小鼠在CFA免疫后没有发生LN肥大。在使用小鼠模型的初步研究中，我们还确定了CFA免疫后，朗格汉斯细胞、特化的真皮dc和肥大细胞对LN肥大至关重要。我们假设来自LC的LIGHT与膜LT协调，调节LV/HEV的激活和增殖，以及白细胞向LN的迁移，以响应免疫损伤，导致LN肥大。具体来说，我们将探索来自朗格汉斯细胞的光是否对通过LT2R信号激活肥大细胞产生炎症介质以促进lv和hev的快速发展至关重要。我们还将研究B细胞是否是LN肥大所需的膜LT的来源，以及LT如何与LIGHT协调以放大HEV激活并促进LV/HEV内皮细胞生长。在目的1中，我们将通过确定哪些细胞在LN肥大期间需要产生和响应LIGHT来研究LIGHT如何在细胞水平上介导LN肥大。我们将测试朗格汉斯细胞是否是LN肥大的必需产光细胞。我们还将识别光反应细胞，根据我们的初步数据，我们假设这是肥大细胞。在目标2中，我们将研究LIGHT如何在分子水平上介导LN肥大。我们将定义LIGHT通过肥大细胞激活和TNF-1产生直接和/或间接调节LV/HEV内皮细胞的分子机制。我们还将研究LIGHT和TNF-1在疫苗接种早期如何协调LV/HEV激活。在目的3中，我们将测试B细胞是否是LN肥大的主要LT来源，并确定LIGHT和LT在LN肥大过程中是否以及如何合作。在目的4中，我们将确定光介导的LN肥大在肿瘤免疫中的作用。我们将定义光介导的（淋巴）血管生成在抗肿瘤T细胞启动中的作用，并探索使用Ad-LIGHT作为辅助剂来增强（淋巴）血管生成和DC/T细胞迁移以改善肿瘤免疫治疗的治疗潜力。总之，我们的研究将阐明在炎症反应中驱动LN肥大的细胞和分子机制，并研究光介导的DC迁移在功能性抗肿瘤免疫反应和更有效疫苗发展中的作用。

DESCRIPTION (provided by applicant): Rapid development of lymphatic vessels (LV) and high endothelial venules (HEV) in peripheral tissues leads to hypertrophy of draining lymph nodes (LN) during inflammation/vaccination, but the molecular mechanism regulating LN hypertrophy is poorly understood. Lymphotoxin (LT), TNF, mast cells, and dendritic cells have all been implicated in the regulation of LN hypertrophy after vaccination or during inflammation. Unexpectedly but intriguingly, our preliminary studies have revealed that LIGHT (TNFRSF14), which shares the LT2R receptor with LT, is also required for LN hypertrophy, since LIGHT KO mice fail to undergo LN hypertrophy after CFA immunization. In preliminary studies using mouse models, we have also determined that Langerhans' cells, specialized dermal DCs, and mast cells are essential for LN hypertrophy after CFA immunization. We hypothesize that LIGHT from LC coordinates with membrane LT to regulate LV/HEV activation and proliferation as well as leukocyte migration into the LN in response to immune insult, leading to LN hypertrophy. Specifically, we will explore whether LIGHT from Langerhans' cells is essential to activate mast cells via LT2R signaling to produce inflammatory mediators for rapid development of LVs and HEVs. We will also study whether B cells are the source of membrane LT required for LN hypertrophy, and how LT coordinates with LIGHT to amplify the HEV activation and promote LV/HEV endothelial cell growth. In aim 1, we will study how LIGHT mediates LN hypertrophy on a cellular level by determining which cells are required to produce and respond to LIGHT during LN hypertrophy. We will test whether Langerhans' cells are the essential LIGHT-producing cells for LN hypertrophy. We will also identify LIGHT-responding cells, which we hypothesize to be mast cells based on our preliminary data. In aim 2, we will study how LIGHT mediates LN hypertrophy on a molecular level. We will define the molecular mechanisms by which LIGHT regulates LV/HEV endothelial cells directly and/or indirectly through mast cell activation and TNF-1 production. We will also investigate how LIGHT and TNF-1 coordinates for LV/HEV activation at the early stage of vaccination. In aim 3, we will test whether B cells are major source of LT for LN hypertrophy and determine whether and how LIGHT and LT cooperate during LN hypertrophy. In aim 4, we will determine the role of LIGHT-mediated LN hypertrophy in tumor immunity. We will define the role of LIGHT-mediated (lymph)angiogenesis in antitumor T cell priming and explore the therapeutic potential of using Ad-LIGHT as an adjuvant to enhance (lymph)angiogenesis and DC/T cell migration for improved tumor immunotherapy. In sum, our study will elucidate cellular and molecular mechanisms that drive LN hypertrophy in response to inflammation, as well as examining the role of LIGHT-mediated DC migration in the development of functional anti-tumor immune responses and more effective vaccines. PUBLIC HEALTH RELEVANCE: Lay summary Understanding the process of LN hypertrophy and defining the parameters regulating leukocyte immune cell migration will help us identify ways to therapeutically manipulate immune responses for better protection against infection, cancer and other immune-mediated diseases. Our study will reveal the cellular and molecular mechanisms underlying LN hypertrophy. This knowledge will be of utmost importance to provide new and novel strategies to more effectively modulate immune responses for the protection against infection and cancer.