新型纳米肽HD5-myr通过线粒体外膜电压依赖性门控通道VDAC-1调控巨噬细胞线粒体功能复苏在脓毒症治疗中的作用及其机制研究

巨噬细胞线粒体功能障碍是脓毒症器官功能损伤的重要机制。近年来线粒体功能复苏在脓毒症器官功能恢复中的作用备受关注，但其机制尚不明确。线粒体外膜电压依赖性门控通道VDAC-1参与ATP和离子等物质在线粒体、胞浆间的转运，是多种疾病的治疗靶点。本课题组前期研发的新型纳米肽HD5-myr在疏水力驱动下形成纳米胶束，被巨噬细胞内吞效果明显增强，并能改善脓毒症小鼠组织损伤及死亡率；我们计算机模拟筛选提示HD5-myr可与VDAC-1直接结合；进一步发现它能增加LPS刺激的巨噬细胞线粒体氧利用和ATP生成，并调节钙离子浓度。因此我们推测：HD5-myr通过VDAC-1调节巨噬细胞线粒体功能复苏，改善脓毒症预后。本项目拟从整体动物、细胞、细胞器、分子水平，深入解析HD5-myr对脓毒症中巨噬细胞线粒体功能复苏：能量生成、钙离子平衡和氧化应激功能的调控作用，并探讨其分子机制，为脓毒症治疗提供新思路。

Mitochondrial dysfunction of macrophages is one of important mechanisms of organ function damage in sepsis. In recent years, the role of mitochondrial resuscitation in organ function recovery has received much attention, but its mechanism remains unclear. VDAC1, a voltage-dependent channel in mitochondrial outer membrane, has been shown to be involved in transport of ATP, ions and other substances between mitochondrion and cytoplasm, and is a therapeutic target for many diseases. The novel nanopeptide HD5-myr developed by our group could self-assemble into nano-micelles in aqueous phase, which made them to be effectively engulfed by macrophages. In addition, we found that HD5-myr alleviated tissue damage and mortality in septic mice. Interestingly, our molecular docking and simulation study indicated HD5-myr could directly bind to VDAC-1. Further experiments showed that HD5-myr could increase mitochondrial oxygen consumption, ATP production, and regulate calcium ion concentration in LPS-stimulated macrophages. Therefore, we hypothesize that HD5-myr regulates mitochondrial resuscitation in macrophages through VDAC-1 and then improves the outcome of sepsis. The present project will dissect the effect of HD5-myr on macrophage mitochondrial resuscitation such as bioenergy synthesis, calcium balance and oxidative stress from the animal, cellular, organelle and molecular levels, and explore the signaling pathway. This study will provide a novel therapeutic insight in the management of sepsis.