TRPC4-DEPENDENT CYTOSOLIC CALCIUM SIGNALS COORDINATE INTERENDOTHELIAL FORCES THAT ELICIT GAP FORMATION

TRPC4 依赖的细胞溶质钙信号协调引起间隙形成的内皮间力

• 批准号: 9766818
• 负责人: NINGYONG XU
• 金额: $ 6.37万
• 依托单位: UNIVERSITY OF SOUTH ALABAMA
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-09-01 至 2021-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9766818
• 关键词: Acute; Acute Lung Injury; Adherens Junction; Agonist; Alveolar; Calcium Signaling; Calcium ion; Cell membrane; Cells; Color; Disease; Edema; Endothelial Cells; Endothelium; Inflammation; Inflammatory; Intensive Care; Intensive Care Units; Intercellular Junctions; Ions; Knock-out; Lead; Liquid substance; Lung; Lung Inflammation; Maps; Morbidity - disease rate; Patients; Permeability; Proteins; Pulmonary Edema; Rest; Testing; Tissues; Vascular Endothelium; Vascular Permeabilities; design; mechanical properties; monolayer; mortality; prevent; receptor; therapeutic target; vascular endothelial cadherin-2

Project Summary Acute lung injury is a disorder of acute inflammation that causes disruption of the pulmonary endothelial barrier and contributes a significant amount of morbidity and mortality in the intensive care unit. Endothelial barrier integrity is critically determined by endothelial cytosolic calcium ion (Ca2+) transients that are activated by the plasma membrane store-operated Ca2+ entry (ISOC) channels. One of the channel subunits, canonical transient receptor potential 4 (TRPC4) protein, critically regulates channel activation and Ca2+ influx. Elevation of cytosolic Ca2+ is sufficient to induce interendothelial gaps in extra-alveolar segments and cause pulmonary edema. However, the mechanism by which TRPC4-dependent Ca2+ influx disrupts adherens junction and coordinates interendothelial forces is poorly understood and is the focus of this application. Cytosolic Ca2+ is not stable but rather fluctuates within a confluent endothelial monolayer. TRPC4 contributes to these basal cytosolic Ca2+ transients. Inflammatory agonists induce Ca2+ influx by activating the TRPC4 ISOC channel leading to a marked elevation of cytosolic Ca2+, which causes endothelial cell retraction and gap formation. However, it is unknown whether these TRPC4-dependent transient increases in cytosolic Ca2+ cause increases in the coordination of interendothelial forces, interendothelial gap formation, and lung edema. Inflammatory diseases are related to changes in mechanical properties of cells and tissues. Intercellular forces are spatially heterogeneous, highly cooperative, and aligned into force chains. During inflammation, disruption of the vascular endothelial barrier is partially initiated through cytoskeletal contraction of a group of cells. The resulting increased contractile forces propagate across neighboring cells via intercellular junctions to increase interendothelial force coordination and correlation, increase intracellular force alignment and extend force chains far outside the gap regions. A large accumulation of contractile forces may eventually exceed the maximum force that an adherens junction can withstand and cause the formation of an interendothelial gap. An interendothelial gap also may form at a tri-junctional (tricellular junction) point where force chains are misaligned and may pull the adherens junction apart. However, it is unknown how TRPC4-dependent cytosolic Ca2+ transients are related to interendothelial force correlation at baseline and after agonist challenge. This proposal tests the overall HYPOTHESIS that TRPC4 activation triggers unique cytosolic Ca2+ transients that are sufficient to increase interendothelial force correlation and promote gap formation, pulmonary permeability, and pulmonary edema.

项目摘要 急性肺损伤是一种急性炎症的紊乱，导致肺内皮屏障的破坏。 在重症监护病房中造成了相当大的发病率和死亡率。内皮屏障完整性 是由血浆激活的内皮细胞内钙离子(钙离子)瞬变决定的 膜储存操作的钙内流(ISOC)通道。通道亚基之一，典型的瞬时受体 潜在4(TRPC4)蛋白，对通道激活和钙内流起关键调节作用。细胞内钙离子升高是 足以引起肺泡外段内皮细胞间隙并引起肺水肿。然而， TRPC4依赖的钙离子内流破坏粘着连接和配位的机制 血管内皮细胞间作用力知之甚少，是本应用的重点。 细胞内钙离子不是稳定的，而是在融合的内皮单层内波动。TRPC4有助于 这些基础胞浆钙瞬变。炎症激动剂通过激活TRPC4 ISOC诱导钙内流 导致细胞内钙离子显著升高的通道，导致内皮细胞收缩和缝隙形成。 然而，目前尚不清楚这些依赖于TRPC4的胞浆钙离子的瞬时增加是否会导致增加 在内皮间力、内皮间隙形成和肺水肿的协调中。 炎症性疾病与细胞和组织机械性能的改变有关。细胞间 力量在空间上是不同的，高度合作，并排列成力链。在发炎期间， 血管内皮屏障的破坏部分是通过一组细胞骨架的收缩来启动的 细胞。由此产生的增强的收缩力通过细胞间连接在相邻细胞之间传播，从而 增加内皮间力量的协调和关联，增加细胞内力量的对准和延伸 远离缝隙区域的力链。大量的收缩力量的积累最终可能超过 附着连接所能承受的最大力，并导致内皮间间隙的形成。一个 内皮间间隙也可以在三连接(三细胞连接)点处形成，在该点力链 未对准，并可能将粘连结合部拉开。然而，目前尚不清楚依赖TRPC4的胞浆是如何 钙瞬变与基础状态和激动剂激发后的内皮间力相关。这项建议 测试TRPC4激活触发独特的胞浆钙瞬变的总体假设，该瞬间足以 增加内皮间力相关性，促进缝隙形成、肺通透性和肺组织 浮肿。