SR-B1hi巨噬细胞新亚群影响呼吸机诱导肺损伤后组织修复的机制研究

Tissue repair following ventilator induced lung injury (VILI) is closely related to the patient prognosis. It plays an important role that macrophage maintain pro-inflammatory response in tissue repair and fibrogenesis, predominantly producing energy by anaerobic glycolysis, is a novel mechanism to induce macrophages pro-inflammation . However, it is still poorly known what the role of Warburg-effect-dependent inflammation plays in tissue repair following VILI. Scavenger receptor (SR) family have been proved to play a dual pivotal roles as metabolic regulator and inflammatory activator in macrophages. Previously, we found the VILI mouse model exhibited an increased expression of SR family class B type 1 (SR-B1). SR-B1hi macrophage differentiated as a new subset . Our preliminary result also showed this subset was characterized by enhanced Warburg effect and persistent pro-inflammation response. SR-B1 knockout promoted lung tissue repair and suppressed fibrosis after VILI. Consequently, we hypothesize : infiltrated macrophages will develop into SR-B1hi new subset induced by death cell phagocytosis following VILI；the novel subset reacts by forming a multi- protein complex known as NLRP3 inflammasome via Warburg effect , resulting in persistent inflammation activation; the metabolic and pro-inflammatory changes leads to lung tissue repair suppression and pulmonary fibrosis; lung protective ventilation may improve repair via suppressing above signaling pathway. In this study, we plan to prove our hypothesis in vivo through using the wild type, SR-B1 knockout and bone marrow transplantation mice bone marrow transplantation mice with VILI and protective ventilation model. Moreover, macrophages with alveolar epithelial cells or fibroblasts will be co-cultured in vitro. Flow cytometry analysis and HPLC-MS will be applied to reveal SR-B1-mediated cross-talk between metabolism and inflammation in the repair phage. Within this study, we anticipate to investigate the underlying mechanism of SR-B1hi macrophage new subset in tissue repair and fibrosis following VILI, and explore a novel therapeutic target to improve outcome.

呼吸机诱导肺损伤(VILI)后组织修复与患者预后密切相关。巨噬细胞持续炎症激活直接影响修复。以无氧糖酵解为主的Warburg效应能持续激活巨噬细胞炎症，但是否调控VILI后组织修复尚不清楚。清道夫受体（SR）对代谢和炎症均有调控作用，我们前期在VILI模型上发现巨噬细胞SR家族成员B1表达上调，分化为SR-B1hi新亚群，Warburg效应增强；SR-B1敲除小鼠纤维化改善。据此提出假说：VILI后巨噬细胞分化形成SR-B1hi新亚群，代谢上表现为Warburg效应，激活 NLRP3炎症小体维持炎症状态，导致修复障碍和纤维化，肺保护性通气通过上述机制改善修复。我们拟复制野生型和SR-B1敲除小鼠 VILI 模型，与肺保护性通气模型对比，分选原代巨噬细胞，利用液相色谱-串联质谱、细胞共培养等方法研究巨噬细胞亚群和功能变化，以期揭示该通路在VILI后组织修复中的机制，为改善预后提供分子靶点。

呼吸机诱导肺损伤（VILI)）后组织修复与机械通气患者预后密切相关。巨噬细胞持续炎症激活直接影响肺组织修复。我们前期研究在VILI模型上发现以无氧糖酵解为主的Warburg效应能持续激活巨噬细胞炎症，参与死亡细胞吞噬的巨噬细胞膜蛋白清道夫受体（SR）家族成员B1表达上调，分化为SR-B1hi新亚群，胞内Warburg效应增强，促炎因子IL-1β、IL-18释放增加；SR-B1敲除小鼠肺组织修复优于野生型小鼠。但VILI发生后，巨噬细胞SR-B1分子及其介导的下游通路如何同时影响胞内代谢与炎症状态，并参与组织损伤与修复尚不清楚。 据此，本项目围绕代谢方式转变介导的巨噬细胞炎症激活参与VILI后组织修复这一科学问题，开展后续研究。建立野生型和SR-B1敲除小鼠VILI模型，与肺保护性通气模型对比，利用液相色谱-串联质谱、细胞共培养等方法，以巨噬细胞亚群和功能变化为核心，在分子、细胞及动物整体水平阐明SR-B1作为枢纽分子实现代谢与炎症网络crosstalk，探讨该分子影响葡萄糖代谢方式并调控巨噬细胞炎症表型的机制，揭示了SR-B1hi巨噬细胞新亚群参与VILI后组织修复的机制。我们验证了科学假说：呼吸机诱导肺损伤后，巨噬细胞在参与死亡细胞清除过程中分化形成SR-B1hi新亚群，SR-B1分子是联系代谢与炎症的枢纽分子，激活下游PI3K-mTOR-Akt1 -HIF-1α通路，使该亚群在代谢上表现出以无氧糖酵解为主要获能方式的Warburg效应，通过 NLRP3炎症小体维持炎症激活状态，导致VILI后组织修复障碍和纤维化发生；肺保护性通气能通过上述机制改善修复，减少纤维化的发生。本研究结果为改善 VILI 后组织修复提供了潜在靶点，为优化机械通气治疗策略提供理论和实验依据。在课题资助下同时开展了VILI后肺损伤和修复的转录组学和代谢组学研究，筛选出一系列与炎症细胞分化、免疫调控、代谢重编程相关的核心信号通路，初步开展了以下呼吸道病毒感染所致ARDS患者接受机械通气过程中糖、脂质代谢谱的研究。上述研究丰富了我们对于VILI后肺损伤的病理生理认知，也为后续在机械通气患者中进行生物标志物验证、气压伤预警模型建立和干预靶点研发，提供了转化医学思路和证据。