脓毒症中单核细胞线粒体危险相关分子模式的胞吐作用抑制中性粒细胞趋化性。
Monocyte exocytosis of mitochondrial danger-associated molecular patterns in sepsis suppresses neutrophil chemotaxis.
机构信息
From the Institute of Molecular Biomedicine (B.K., B.V.), Comenius University, Bratislava, Slovakia; Department of Surgery (J.P., W.H., H.I.K., M.B.Y., L.E.O., K.I., C.J.H.), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachussets; Department of Emergency Medicine (W-.Y.K.), Seoul National University College of Medicine Seoul, Korea; College of Nursing (Q.Z.), Harbin Medical School, Daqing, China; and Departments of Biology and Biological Engineering (M.B.Y.), Massachusetts Institute of Technology, Boston, Massachussets.
出版信息
J Trauma Acute Care Surg. 2021 Jan 1;90(1):46-53. doi: 10.1097/TA.0000000000002973.
BACKGROUND
Trauma and sepsis both increase the risk for secondary infections. Injury mobilizes mitochondrial (MT) danger-associated molecular patterns (mtDAMPs) directly from cellular necrosis. It is unknown, however, whether sepsis can cause active MT release and whether mtDAMPs released by sepsis might affect innate immunity.
METHODS
Mitochondrial release from human monocytes (Mo) was studied after LPS stimulation using electron microscopy and using fluorescent video-microscopy of adherent Mo using Mito-Tracker Green (MTG) dye. Release of MTG+ microparticles was studied using flow cytometry after bacterial stimulation by size exclusion chromatography of supernatants with polymerase chain reaction (PCR) for mitochondrial DNA (mtDNA). Human neutrophil (PMN), chemotaxis, and respiratory burst were studied after PMN incubation with mtDNA.
RESULTS
LPS caused Mo to release mtDAMPs. Electron microscopy showed microparticles containing MT. mtDNA was present both in microvesicles and exosomes as shown by PCR of the relevant size exclusion chromatography bands. In functional studies, PMN incubation with mtDNA suppressed chemotaxis in a dose-dependent manner, which was reversed by chloroquine, suggesting an endosomal, toll-like receptor-9-dependent mechanism. In contrast, PMN respiratory burst was unaffected by mtDNA.
CONCLUSION
In addition to passive release of mtDAMPs by traumatic cellular disruption, inflammatory and infectious stimuli cause active mtDAMP release via microparticles. mtDNA thus released can have effects on PMN that may suppress antimicrobial function. mtDAMP-mediated "feed-forward" mechanisms may modulate immune responses and potentially be generalizable to other forms of inflammation. Where they cause immune dysfunction the effects can be mitigated if the pathways by which the mtDAMPs act are defined. In this case, the endosomal inhibitor chloroquine is benign and well tolerated. Thus, it may warrant study as a prophylactic antiinfective after injury or prior sepsis.
背景
创伤和败血症都会增加继发感染的风险。损伤直接从细胞坏死中动员线粒体（MT）危险相关分子模式（mtDAMPs）。然而，尚不清楚败血症是否会导致 MT 主动释放，以及败血症释放的 mtDAMPs 是否会影响先天免疫。
方法
使用电子显微镜研究 LPS 刺激后人单核细胞（Mo）的线粒体释放，使用荧光视频显微镜研究粘附 Mo 中使用 Mito-Tracker Green（MTG）染料的线粒体释放。使用细菌刺激后的大小排除色谱法研究 MTG+微粒体的释放，并用聚合酶链反应（PCR）对上清液中的线粒体 DNA（mtDNA）进行检测。用 mtDNA 孵育中性粒细胞（PMN）后研究 PMN 趋化性和呼吸爆发。
结果
LPS 导致 Mo 释放 mtDAMPs。电子显微镜显示含有 MT 的微粒体。PCR 显示大小排除色谱法相关条带中存在微囊泡和外泌体中的 mtDNA。在功能研究中，PMN 与 mtDNA 孵育以剂量依赖性方式抑制趋化性，氯喹可逆转该作用，提示为内体、 Toll 样受体 9 依赖性机制。相比之下，PMN 呼吸爆发不受 mtDNA 影响。
结论
除了创伤性细胞破坏引起的 mtDAMPs 被动释放外，炎症和感染性刺激还通过微粒体引起 mtDAMP 的主动释放。因此，释放的 mtDNA 可能对 PMN 产生影响，从而抑制抗菌功能。mtDAMP 介导的“正反馈”机制可能调节免疫反应，并可能推广到其他炎症形式。如果确定 mtDAMPs 作用的途径，则可以减轻它们引起的免疫功能障碍的影响。在这种情况下，内体抑制剂氯喹是良性且耐受良好的。因此，它可能值得作为创伤后或败血症前的预防性抗感染药物进行研究。
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