Mechanisms of Lymphatic Regression and Recurrent Lymphangiogenesis

项目摘要/摘要 损伤引起的炎症沿着两种轨迹之一发展：伤口愈合或慢性炎症。 淋巴管重塑通过调节液体动态平衡和免疫功能参与了这两个过程。 细胞流量流向引流的淋巴结。淋巴管内皮细胞(LECs)通过以下途径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随后会消退为炎症 治愈，支持伤口愈合。伤口愈合的失调损害了左心室的退缩，并导致 复发性LA和慢性炎症。控制持续性左心室退缩与激活的机制 复发的LA尚不清楚。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，预防或逆转慢性炎症。这项提案的总体目标是界定 创面愈合过程中LV退缩的细胞事件，并识别 对于复发的左房，重新激活退行性左室段。我们的初步数据显示巨噬细胞 协调淋巴重塑。我们假设极化不同的巨噬细胞表现不同 在退行性和复发性LA中的作用，首先通过吞噬凋亡的LECs和 后来详细阐述了LA因子以重新激活LECs和降解胶原以支持片段迁移和 吻合。我们将用两个具体的目标来检验这一假设：(1)定义 巨噬细胞的存在和极化调节复发性LA中LEC的消退和再激活； (2)识别从LV回归向复发LA过渡的信号。第一个目标将使用一个 新型双色转基因小鼠模型追踪EGFP+巨噬细胞与 活体显微镜观察番茄+晶状体上皮细胞。第二个目标将使用一种创新的体内方法来识别 并验证复发LA的候选蛋白质调节因子与角膜配对的蛋白质细胞因子阵列 微口袋模型。这将扩大LEC和巨噬细胞功能表型的基本知识，并 为淋巴功能障碍、巨噬细胞调节和慢性炎症的治疗进展提供信息。

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.