Mechanisms of Lymphatic Regression and Recurrent Lymphangiogenesis

项目总结/摘要 损伤诱导的炎症沿着两种轨迹之沿着发展：伤口愈合或慢性炎症。 淋巴管（LV）重塑通过调节体液平衡和免疫调节来促进这两个过程。 细胞流向引流淋巴结。淋巴管内皮细胞（LEC）通过以下方式对急性炎症作出反应： 通过淋巴管生成（LA）形成新的LV。这些新合成的LV然后作为炎症消退 解决，支持伤口愈合。伤口愈合的失调损害LV消退并导致 复发性LA和慢性炎症。控制持续LV消退与激活的机制 复发性LA未知。我们的长期目标是制定针对LV重塑的策略，以促进 伤口愈合和预防或逆转慢性炎症。本提案的总体目标是确定 在伤口愈合期间LV退化的细胞事件，并鉴定 重新激活退化的LV碎片以治疗复发性LA。我们的初步数据表明巨噬细胞 协调淋巴重塑。我们假设，差异极化的巨噬细胞表现出不同的功能， 在退行性和复发性LA中起作用，首先支持凋亡LEC的吞噬导致的碎片化， 随后，阐述LA因子以重新激活LEC并降解胶原蛋白以支持片段迁移， 吻合术我们将通过两个具体目标来检验这一假设：（1）定义 巨噬细胞的存在和极化在复发性LA的消退和再活化中调节LEC命运;以及 (2)识别控制从LV消退到复发LA转变的信号。第一个目标将采用一个 一种新的双色转基因小鼠模型，用于跟踪eGFP+巨噬细胞的相互作用和命运， 通过活体显微镜观察tdTomato+ LEC。第二个目标将使用创新的体内方法来识别 并验证复发性LA的候选蛋白质调节剂，将蛋白质细胞因子阵列与角膜 微袋模型这将扩展LEC和巨噬细胞功能表型的基础知识， 为淋巴功能障碍、巨噬细胞调节和慢性炎症提供治疗发展信息。

Project Summary/Abstract Injury-induced inflammation progresses along one of two trajectories: wound healing or chronic inflammation. Lymphatic vessel (LV) remodeling contributes to both processes by regulating fluid homeostasis and immune cell traffic to draining lymph nodes. Lymphatic endothelial cells (LECs) respond to acute inflammation by forming new LVs through lymphangiogenesis (LA). These newly-synthesized LVs then regress as inflammation resolves, supporting wound healing. Dysregulation of wound healing impairs LV regression and leads to recurrent LA and chronic inflammation. The mechanisms that govern sustained LV regression vs. activation of recurrent LA are unknown. Our long-term goal is to develop strategies targeting LV remodeling to promote wound healing and prevent or reverse chronic inflammation. The overall objective of this proposal is to define the cellular events of LV regression during wound healing and to identify the cellular events and signals that reactivate regressed LV fragments for recurrent LA. Our preliminary data indicate that macrophages critically coordinate lymphatic remodeling. We hypothesize that differentially polarized macrophages perform distinct functions in regression and recurrent LA, first supporting fragmentation by engulfment of apoptotic LECs and later elaborating LA factors to reactivate LECs and degrading collagen to support fragment migration and anastomosis. We will test this hypothesis with two specific aims: (1) Define the mechanisms by which macrophage presence and polarization regulate LEC fate in regression and reactivation in recurrent LA; and (2) Identify signals governing the transition from LV regression to recurrent LA. The first aim will employ a novel dual-color transgenic mouse model to track the interactions and fates of eGFP+ macrophages and tdTomato+ LECs by intravital microscopy. The second aim will use an innovative in vivo approach to identify and validate candidate protein regulators of recurrent LA, pairing protein cytokine arrays with the corneal micropocket model. This will expand basic knowledge of LEC and macrophage functional phenotypes and inform therapeutic development for lymphatic dysfunction, macrophage modulation, and chronic inflammation.