Nrf2调控内皮祖细胞代谢重编程促进肉鸡肺血管丛样病变形成的机制

Pulmonary arterial hypertension (PAH) is a common disease in broiler chickens but there remains no effective treatment for it. Currently, plexiform lesions in pulmonary arteries are increasingly considered to be a key factor involved in the development of PAH. However, the mechanisms underlying this process remain largely unclear. Our previous studies indicate that formation of plexiform lesions is initiated by the abnormal differentiation of endothelial progenitor cells (EPCs) to macrophages, which is associated with local inflammatory response. In our preliminary study, we found that Nrf2 was strongly expressed in the early-stage plexiform lesions. In the present project, we aim to confirm the differentiation direction of EPCs during the development of plexiform lesions by using living cell tracking technique. Next, we will use a cell model of inflammation to analysis the metabolic networks that direct EPCs to macrophage differentiation, and to explore whether this process is associated with Nrf2-mediated signal pathways by using untargeted metabolomics, RNA-seq and RNAi techniques, systematically explaining how inflammation induces macrophage differentiation of EPCs by reprogramming their metabolic pathways. Our findings will further reveal the cellular and molecular mechanisms of the formation of plexiform lesions, thereby providing new targets for the intervention of the lesions and new theoretical basis for PAH control.

肺动脉高压（PAH）是肉鸡的一种常见疾病，尚无理想的防治措施。目前认为，肺血管丛样病变在PAH的发生发展过程中发挥重要作用，但其发生的机制不明。课题组前期的研究提示内皮祖细胞（EPCs）向巨噬细胞分化是决定丛样病变形成的起始环节，这一过程与局部炎症反应有关。我们在预实验中发现转录因子Nrf2在早期丛样病变部位高表达。本项目拟采用活细胞示踪技术，进一步明确丛样病变形成过程中EPCs的分化方向。在此基础上，利用体外细胞模型，采用非靶向代谢组学技术、RNA-seq和RNAi等技术，解析炎症刺激下EPCs向巨噬细胞分化的代谢调控网络，并揭示Nrf2对这一过程的调控作用及信号转导机制，系统阐释炎症反应如何通过诱导EPCs发生代谢重编程而促进其向巨噬细胞分化。研究结果不仅可进一步揭示肺血管丛样病变的细胞学和分子机制，同时也有望发现干预丛样病变形成的新靶点，为防控肉鸡PAH提供新的理论依据。

肺动脉高压（PAH）是肉鸡的一种常见疾病，对肉鸡业造成严重危害，目前尚无理想的防治措施。丛样病变（plexiform lesion）是PAH的特征性病变，可导致肺血管完全阻塞，但其细胞起源和发生机制不明。我们前期的研究证实丛样病变的形成与早期内皮祖细胞（eEPCs）功能障碍有关，但引起eEPCs功能障碍的原因及机制尚不清楚。本项目采用多种技术手段，研究了PAH促发因素（慢性炎症反应、肺血流量升高）对eEPCs命运和丛样病变形成的调控作用及机制。结果表明：慢性炎症和血流量升高均可诱导eEPCs向巨噬细胞转化，促进丛样病变形成；在eEPCs向巨噬细胞转化过程中，转录因子Nrf2表达增强且持续活化，敲低Keap1可促进一过程，表明Nrf2持续活化介导了eEPCs向巨噬细胞转化；Nrf2持续活化可促进eEPCs中甘露糖受体C-1型（MRC1）表达，并引起以G6PD表达升高、PGD表达下调为特征的代谢重构，从而促进eEPCs向巨噬细胞转化；丛样病变中的eEPCs自噬缺乏，给予雷帕霉素可下调Nrf2表达，从而抑制丛样病变形成。本项目研究结果表明Nrf2调控eEPCs向巨噬细胞转化是丛样病变形成的重要机制，Nrf2可作为干预丛样病变形成的靶点。