1 Department of Physiological Sciences, Eastern Virginia Medical School, Norfolk, Virginia.
2 Texas Lung Injury Institute, the University of Texas Health Science Center at Tyler, Tyler, Texas.
Am J Respir Cell Mol Biol. 2018 Nov;59(5):635-647. doi: 10.1165/rcmb.2017-0364OC.
Studies showed that TRIM72 is essential for repair of alveolar cell membrane disruptions, and exogenous recombinant human TRIM72 protein (rhT72) demonstrated tissue-mending properties in animal models of tissue injury. Here we examine the mechanisms of rhT72-mediated lung cell protection in vitro and test the efficacy of inhaled rhT72 in reducing tissue pathology in a mouse model of ventilator-induced lung injury. In vitro lung cell injury was induced by glass beads and stretching. Ventilator-induced lung injury was modeled by injurious ventilation at 30 ml/kg tidal volume. Affinity-purified rhT72 or control proteins were added into culture medium or applied through nebulization. Cellular uptake and in vivo distribution of rhT72 were detected by imaging and immunostaining. Exogenous rhT72 maintains membrane integrity of alveolar epithelial cells subjected to glass bead injury in a dose-dependent manner. Inhaled rhT72 decreases the number of fatally injured alveolar cells, and ameliorates tissue-damaging indicators and cell injury markers after injurious ventilation. Using in vitro stretching assays, we reveal that rhT72 improves both cellular resilience to membrane wounding and membrane repair after injury. Image analysis detected rhT72 uptake by rat alveolar epithelial cells, which can be inhibited by a cholesterol-disrupting agent. In addition, inhaled rhT72 distributes to the distal lungs, where it colocalizes with phosphatidylserine detection on nonpermeabilized lung slices to label wounded cells. In conclusion, our study showed that inhaled rhT72 accumulates in injured lungs and protects lung tissue from ventilator injury, the mechanisms of which include improving cell resilience to membrane wounding, localizing to injured membrane, and augmenting membrane repair.
研究表明，TRIM72 对于修复肺泡细胞膜破裂是必不可少的，外源性重组人 TRIM72 蛋白（rhT72）在组织损伤的动物模型中显示出组织修复特性。在这里，我们研究了 rhT72 在体外介导肺细胞保护的机制，并测试了吸入 rhT72 在减少呼吸机诱导的肺损伤小鼠模型中组织病理学损伤的疗效。体外肺细胞损伤是通过玻璃珠和拉伸诱导的。通过损伤性通气（潮气量 30ml/kg）模拟呼吸机诱导的肺损伤。亲和纯化的 rhT72 或对照蛋白被添加到培养基中或通过雾化应用。通过成像和免疫染色检测 rhT72 的细胞摄取和体内分布。外源性 rhT72 以剂量依赖性方式维持玻璃珠损伤的肺泡上皮细胞的膜完整性。吸入 rhT72 可减少致命性损伤的肺泡细胞数量，并改善损伤性通气后的组织损伤指标和细胞损伤标志物。通过体外拉伸试验，我们揭示 rhT72 可改善细胞对膜损伤的弹性和损伤后膜修复。图像分析检测到 rhT72 被大鼠肺泡上皮细胞摄取，这可被胆固醇破坏剂抑制。此外，吸入的 rhT72 分布到远端肺部，在那里与非渗透性肺切片上的磷脂酰丝氨酸检测共定位，以标记受伤的细胞。总之，我们的研究表明，吸入的 rhT72 积聚在受损的肺部并保护肺组织免受呼吸机损伤，其机制包括提高细胞对膜损伤的弹性、定位于受损的膜以及增强膜修复。
