Zanotti Giorgio, Casiraghi Monica, Abano John B, Tatreau Jason R, Sevala Mayura, Berlin Hilary, Smyth Susan, Funkhouser William K, Burridge Keith, Randell Scott H, Egan Thomas M
Division of Cardiothoracic Surgery, Cystic Fibrosis Pulmonary Research and Treatment Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7065, USA.
Am J Physiol Lung Cell Mol Physiol. 2009 Jul;297(1):L52-63. doi: 10.1152/ajplung.90406.2008. Epub 2009 Apr 17.
Toll-like receptors (TLRs) of the innate immune system contribute to noninfectious inflammatory processes. We employed a murine model of hilar clamping (1 h) with reperfusion times between 15 min and 3 h in TLR4-sufficient (C3H/OuJ) and TLR4-deficient (C3H/HeJ) anesthetized mice with additional studies in chimeric and myeloid differentiation factor 88 (MyD88)- and TLR4-deficient mice to determine the role of TLR4 in lung ischemia-reperfusion injury. Human pulmonary microvascular endothelial monolayers were subjected to simulated warm ischemia and reperfusion with and without CRX-526, a competitive TLR4 inhibitor. Functional TLR4 solely on pulmonary parenchymal cells, not bone marrow-derived cells, mediates early lung edema following ischemia-reperfusion independent of MyD88. Activation of MAPKs and NF-kappaB was significantly blunted and/or delayed in lungs of TLR4-deficient mice as a consequence of ischemia-reperfusion injury, but edema development appeared to be independent of activation of these signaling pathways. Pretreatment with a competitive TLR4 inhibitor prevented edema in vivo and reduced actin cytoskeletal rearrangement and gap formation in pulmonary microvascular endothelial monolayers subjected to simulated warm ischemia and reperfusion. In addition to its well-accepted role to alter gene transcription, functioning TLR4 on pulmonary parenchymal cells plays a key role in very early and profound pulmonary edema in murine lung ischemia-reperfusion injury. This may be due to a novel mechanism: regulation of endothelial cell cytoskeleton affecting microvascular endothelial cell permeability.
天然免疫系统中的Toll样受体（TLRs）参与非感染性炎症过程。我们采用了一种小鼠肺门钳夹模型（1小时），在TLR4充足（C3H/OuJ）和TLR4缺陷（C3H/HeJ）的麻醉小鼠中进行15分钟至3小时的再灌注，并对嵌合小鼠、髓样分化因子88（MyD88）缺陷小鼠和TLR4缺陷小鼠进行额外研究，以确定TLR4在肺缺血再灌注损伤中的作用。用人肺微血管内皮单层细胞进行模拟的温暖缺血和再灌注实验，实验中使用和不使用竞争性TLR4抑制剂CRX - 526。仅肺实质细胞上有功能的TLR4，而非骨髓来源细胞上的TLR4，介导缺血再灌注后的早期肺水肿，且不依赖MyD88。由于缺血再灌注损伤，TLR4缺陷小鼠肺中丝裂原活化蛋白激酶（MAPKs）和核因子κB（NF - κB）的激活显著减弱和/或延迟，但水肿的发展似乎与这些信号通路的激活无关。用竞争性TLR4抑制剂预处理可预防体内水肿，并减少模拟温暖缺血和再灌注的肺微血管内皮单层细胞中肌动蛋白细胞骨架重排和间隙形成。除了其公认的改变基因转录的作用外，肺实质细胞上有功能的TLR4在小鼠肺缺血再灌注损伤的极早期和严重肺水肿中起关键作用。这可能是由于一种新机制：调节内皮细胞细胞骨架影响微血管内皮细胞通透性。
