Endothelial glycocalyx loss is integral to increased pulmonary vascular permeability in sepsis-related acute lung injury. Protectin conjugates in tissue regeneration 1 (PCTR1) is a novel macrophage-derived lipid mediator exhibiting potential anti-inflammatory and pro-resolving benefits. PCTR1 was administrated intraperitoneally with 100 ng/mouse after lipopolysaccharide (LPS) challenged. Survival rate and lung function were used to evaluate the protective effects of PCTR1. Lung inflammation response was observed by morphology and inflammatory cytokines level. Endothelial glycocalyx and its related key enzymes were measured by immunofluorescence, ELISA, and Western blot. Afterward, related-pathways inhibitors were used to identify the mechanism of endothelial glycocalyx response to PCTR1 in mice and human umbilical vein endothelial cells (HUVECs) after LPS administration. In vivo, we show that PCTR1 protects mice against lipopolysaccharide (LPS)-induced sepsis, as shown by enhanced the survival and pulmonary function, decreased the inflammatory response in lungs and peripheral levels of inflammatory cytokines such as tumor necrosis factor-α, interleukin-6, and interleukin-1β. Moreover, PCTR1 restored lung vascular glycocalyx and reduced serum heparin sulphate (HS), syndecan-1 (SDC-1), and hyaluronic acid (HA) levels. Furthermore, we found that PCTR1 downregulated heparanase (HPA) expression to inhibit glycocalyx degradation and upregulated exostosin-1 (EXT-1) protein expression to promote glycocalyx reconstitution. Besides, we observed that BAY11-7082 blocked glycocalyx loss induced by LPS in vivo and in vitro, and BOC-2 (ALX antagonist) or EX527 (SIRT1 inhibitor) abolished the restoration of HS in response to PCTR1. PCTR1 protects endothelial glycocalyx via ALX receptor by regulating SIRT1/NF-κB pathway, suggesting PCTR1 may be a significant therapeutic target for sepsis-related acute lung injury.

中文翻译：

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组织再生中的保护素结合物 1 通过 ALX/SIRT1/NF-κB 轴恢复脂多糖诱导的肺内皮糖萼丢失

内皮糖萼丢失是脓毒症相关急性肺损伤肺血管通透性增加的组成部分。组织再生中的保护素结合物 1 (PCTR1) 是一种新型巨噬细胞衍生的脂质介质，具有潜在的抗炎和促分解作用。PCTR1 在脂多糖 (LPS) 攻击后以 100 ng/小鼠腹膜内给药。存活率和肺功能用于评估PCTR1的保护作用。通过形态学和炎性细胞因子水平观察肺部炎症反应。通过免疫荧光、ELISA和Western印迹检测内皮糖萼及其相关关键酶。之后，相关途径抑制剂用于确定 LPS 给药后小鼠和人脐静脉内皮细胞 (HUVEC) 内皮糖萼对 PCTR1 的反应机制。在体内，我们表明 PCTR1 保护小鼠免受脂多糖 (LPS) 诱导的败血症，如提高存活率和肺功能所示，降低肺部炎症反应和外周炎症细胞因子水平，如肿瘤坏死因子-α、白细胞介素- 6、白细胞介素-1β。此外，PCTR1 恢复肺血管糖萼并降低血清硫酸肝素 (HS)、syndecan-1 (SDC-1) 和透明质酸 (HA) 水平。此外，我们发现 PCTR1 下调乙酰肝素酶 (HPA) 表达以抑制糖萼降解并上调 exostosin-1 (EXT-1) 蛋白表达以促进糖萼重建。除了，我们观察到 BAY11-7082 在体内和体外阻止了 LPS 诱导的糖萼丢失，并且 BOC-2（ALX 拮抗剂）或 EX527（SIRT1 抑制剂）消除了响应 PCTR1 的 HS 的恢复。PCTR1 通过调节 SIRT1/NF-κB 通路，通过 ALX 受体保护内皮糖萼，表明 PCTR1 可能是脓毒症相关急性肺损伤的重要治疗靶点。