Mechanical forces regulate leukocyte migration in rapidly deforming tissues

项目摘要 白细胞必须能够渗透和迁移到身体的几乎所有组织中，以便处理 在整个宿主中发生的感染和破坏。化学吸引剂和粘合剂等分子信号 配体在这一过程中至关重要，但免疫细胞也可以感知机械信号并对其做出反应。虽然大多数人 身体的组织是相对静止的，肠道是机械动态的，因为重复的 平滑肌层的收缩，对组织施加压缩、拉伸和剪切力。 这些力量在肠道感染期间发生改变，并在炎症性肠炎中长期失调。 疾病，指出肠道机械和炎症之间的关系。白细胞是 对机械非常敏感，但目前还不清楚它们是否感觉到或对大脑中的机械信号做出反应 直接进入肠道。在啮齿动物模型中研究这些作用力是具有挑战性的，因为肠道组织需要 为了活体成像而被物理固定。在这里，我们建议研究肠道力量的作用 利用斑马鱼系统对免疫细胞功能的影响。肠道T淋巴细胞可直接显示在 该系统无需任何手术操作或组织固定。具有药理学和遗传性 干扰平滑肌功能的工具，我们可以研究肠道T细胞在存在和 无机械变形。在初步数据中，我们发现肠道T细胞通过 相对于皮肤或鳃等静态组织，肠道中的独特策略，其特点是薄， 丝状突起，经历连续的分支以推动T细胞前进。肠梗阻 使用平滑肌抑制剂的运动会严重损害肠道内T细胞的运动性，但不是静态的 像皮肤一样的组织。总而言之，这些结果表明，机械提示决定了T细胞迁移策略 在肠子里。这项研究将研究T细胞如何感知和应对肠道的变形。 具体地说，我们将检验肠道变形激活离子通道Piezo1促进 丝状孢子状迁移。据我们所知，这将是第一个研究肠道力量如何 对肠道免疫的影响和我们的研究结果可能对肠易激综合征的诊断和治疗具有广泛的意义 肠道炎症性疾病。

Project Summary Leukocytes must be able to infiltrate and migrate within essentially all tissues of the body in order to deal with infections and damage that occur throughout the host. Molecular signals like chemoattractants and adhesive ligands are critical for this process, but immune cells also sense and respond to mechanical cues. While most tissues of the body are relatively static, the intestines are mechanically dynamic due to the repetitive contractions of the smooth muscle layers, which apply compressive, stretch, and shear forces to the tissue. These forces are altered during intestinal infections and chronically dysregulated in inflammatory bowel disease, pointing towards a relationship between intestinal mechanics and inflammation. Leukocytes are exquisitely mechanosensitive, but it is presently unknown if they sense or respond to mechanical cues in the intestines directly. Investigating these forces in rodent models is challenging since the intestinal tissue needs to be physically immobilized for intravital imaging. Here, we propose to investigate the role intestinal forces on immune cell function by using the zebrafish system. Intestinal T lymphocytes can be directly visualized in this system without any surgical manipulation or tissue immobilization. With pharmacological and genetic tools that interfere with smooth muscle function, we can study intestinal T cell behavior in the presence and absence of mechanical deformation. In preliminary data, we have found that intestinal T cells migrate by a distinct strategy in the intestines relative to static tissues like the skin or gills, one characterized by thin, filopodia-like protrusions that undergo successive branching to propel the T cell forward. Blocking intestinal movement with smooth muscle inhibitors severely impairs T cell motility within the intestines, but not in static tissues like the skin. Collectively, these results suggest that mechanical cues dictate T cell migration strategies in the intestines. This proposal will investigate how T cells sense and respond to deformation in the intestines. Specifically, we will test the hypothesis that intestinal deformation activates the ion channel Piezo1 to promote filopodia-like migration. To our knowledge, this will be the first study to investigate how intestinal forces influence gut immunity and our findings could have broad implications for the diagnosis and treatment of inflammatory disorders of the gut.