Mechanical Injury Induces Brain Endothelial-Derived Microvesicle Release: Implications for Cerebral Vascular Injury during Traumatic Brain Injury.
Mechanical Injury Induces Brain Endothelial-Derived Microvesicle Release: Implications for Cerebral Vascular Injury during Traumatic Brain Injury.
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DOI：
10.3389/fncel.2016.00043
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发表时间：
2016
影响因子：
5.3
通讯作者：
Ramirez SH
中科院分区：
文献类型：
--
作者：
Andrews AM;Lutton EM;Merkel SF;Razmpour R;Ramirez SH
内皮对由剪切应力和应变变化引起的机械力有反应，这是公认的。然而，我们对创伤性脑损伤（TBI）后血管重塑的理解仍然不完整。最近发表的研究表明，肺和脐内皮细胞产生细胞外微泡（eMV），如微粒，以响应机械力（血流和机械损伤）的变化。然而，迄今为止，还没有研究表明脑内皮细胞是否在TBI后产生eMV。脑内皮是高度特化的并且形成血脑屏障（BBB），其调节溶质向脑中的扩散和运输。这种特化主要是由于相邻内皮细胞之间存在紧密连接蛋白（TJPs）。TBI后，BBB处紧密连接复合物的破坏导致通透性增加，这极大地促进了损伤的第二阶段。因此，我们已经测试了假设，脑内皮细胞响应机械损伤，通过产生eMV，含有脑内皮蛋白，特别是TJPs。在我们的研究中，原代成人脑微血管内皮细胞（BMVEC）进行快速机械损伤，以模拟突然的内皮细胞破坏，可以发生在TBI的原发性损伤阶段。在损伤后2、6、24和48小时从培养基中分离出eMV。eMV的蛋白质印迹分析表明机械损伤后TJP occludin、PECAM-1和ICAM-1的时间依赖性增加。此外，损伤后ARF 6（一种与细胞外囊泡产生相关的小GTPase）的激活增加。为了在体内证实这些结果，使小鼠经受假手术或TBI，并在损伤后24小时收集血浆。使用cryo-EM和流式细胞术从血浆中分离和分析eMV，揭示了脑创伤后含有occludin的囊泡水平升高。这些结果表明，在TBI后，脑内皮通过含有TJP和内皮标志物的eMV的脱落经历血管重塑。这种脱落的检测可能允许一种新的方法，用于实时监测脑血管健康（重塑），BBB状态和神经炎症后的TBI事件。
It is well established that the endothelium responds to mechanical forces induced by changes in shear stress and strain. However, our understanding of vascular remodeling following traumatic brain injury (TBI) remains incomplete. Recently published studies have revealed that lung and umbilical endothelial cells produce extracellular microvesicles (eMVs), such as microparticles, in response to changes in mechanical forces (blood flow and mechanical injury). Yet, to date, no studies have shown whether brain endothelial cells produce eMVs following TBI. The brain endothelium is highly specialized and forms the blood-brain barrier (BBB), which regulates diffusion and transport of solutes into the brain. This specialization is largely due to the presence of tight junction proteins (TJPs) between neighboring endothelial cells. Following TBI, a breakdown in tight junction complexes at the BBB leads to increased permeability, which greatly contributes to the secondary phase of injury. We have therefore tested the hypothesis that brain endothelium responds to mechanical injury, by producing eMVs that contain brain endothelial proteins, specifically TJPs. In our study, primary human adult brain microvascular endothelial cells (BMVEC) were subjected to rapid mechanical injury to simulate the abrupt endothelial disruption that can occur in the primary injury phase of TBI. eMVs were isolated from the media following injury at 2, 6, 24, and 48 h. Western blot analysis of eMVs demonstrated a time-dependent increase in TJP occludin, PECAM-1 and ICAM-1 following mechanical injury. In addition, activation of ARF6, a small GTPase linked to extracellular vesicle production, was increased after injury. To confirm these results in vivo, mice were subjected to sham surgery or TBI and blood plasma was collected 24 h post-injury. Isolation and analysis of eMVs from blood plasma using cryo-EM and flow cytometry revealed elevated levels of vesicles containing occludin following brain trauma. These results indicate that following TBI, the cerebral endothelium undergoes vascular remodeling through shedding of eMVs containing TJPs and endothelial markers. The detection of this shedding potentially allows for a novel methodology for real-time monitoring of cerebral vascular health (remodeling), BBB status and neuroinflammation following a TBI event.