The role of cell surface mechanics in activating the mechanosensitive ion channel Piezo1

细胞表面力学在激活机械敏感离子通道 Piezo1 中的作用

• 批准号: BB/X015831/1
• 负责人: Ewa Paluch
• 金额: $ 81.27万
• 依托单位: University of Cambridge
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FX015831%2F1
• 关键词: role; cell; surface; mechanics; activating

Our body senses both chemical signals, such as smell molecules, and mechanical signals, such as pressure. In a similar way, most cells in our body sense and respond to both chemical and mechanical signals in their environment. However, while our understanding of chemical signalling has increased tremendously over the past decades, much less is currently known about how cells 'feel' mechanical signals such as forces or tissue stiffness. Cells are surrounded by a thin shell mainly consisting of lipids, which is called cell membrane. When cells are exposed to forces, which might, for example, come from a neighbouring cell pulling on it or shear forces exerted by blood flowing by, the cell membrane is deformed. This deformation may be registered by highly specialised proteins located in the membrane that act as force sensors. One of the most important force sensing proteins in the cell membrane is an ion channel (i.e., a 'hollow' protein traversing the membrane that may open like a gate to let ions pass through) called Piezo1. Piezo1 is thought to be activated by an increase in membrane tension, i.e., a force acting in parallel to the membrane, which for example increases when water flows into cells, like the membrane of a balloon gets more tense when air is blown in. However, direct evidence for an activation of Piezo1 by changes in membrane tension in living cells is still scarce, and recent data challenge this assumption. Furthermore, if and how membrane tension in cells changes in response to mechanical signals such as the stiffness of their environment is still poorly understood. The focus of this proposal is on identifying how Piezo1 is activated in response to substrate stiffness in living cells. To address this, a team with long-standing experience in cell biology, mechanobiology and physical biology will develop and exploit diverse approaches to measure and perturb membrane tension either across whole cells or just locally. We will culture cells on custom-built soft substrates and monitor Piezo1 activity in response to well-defined mechanical signals and manipulation of cellular components involved in force generation and force transmission. Ultimately, we will test how cell surface mechanics controls mechanical signalling through Piezo1 in frog embryos, which has important implications for developmental and pathological processes which are accompanied by changes in tissue mechanics, such as neurodegenerative diseases. Any insights gained into how Piezo1 translates a mechanical signal into an intracellular response might reveal new targets for drug development to interfere with age-related problems such as dementia, or even with regenerative processes after neural injury and neurodegenerative diseases, where tissue mechanics - and hence Piezo1-mediated signalling - changes.

我们的身体既能感受到化学信号，如气味分子，也能感受到机械信号，如压力。以类似的方式，我们身体中的大多数细胞都能感知并响应环境中的化学和机械信号。然而，虽然我们对化学信号的理解在过去几十年中有了极大的提高，但目前对细胞如何“感受”机械信号（如力或组织刚度）的了解要少得多。细胞被一层主要由脂质组成的薄壳所包围，称为细胞膜。当细胞暴露于力时，例如，可能来自邻近细胞对它的拉动或血液流动所施加的剪切力，细胞膜变形。这种变形可以通过位于膜中的高度专门化的蛋白质来记录，这些蛋白质充当力传感器。细胞膜中最重要的力传感蛋白之一是离子通道（即，一种“中空”的蛋白质穿过膜，可以像门一样打开，让离子通过）称为Piezo 1。Piezo 1被认为是由膜张力的增加激活的，即，一个平行于膜作用的力，例如当水流入细胞时会增加，就像气球的膜在空气吹进来时会变得更加紧张。然而，活细胞中膜张力的变化激活Piezo 1的直接证据仍然很少，最近的数据挑战了这一假设。此外，细胞膜张力是否以及如何响应机械信号（如环境的硬度）而变化仍然知之甚少。该提案的重点是确定Piezo 1如何响应活细胞中的基底刚度而被激活。为了解决这个问题，一个在细胞生物学、机械生物学和物理生物学方面具有长期经验的团队将开发和利用多种方法来测量和扰动整个细胞或局部的膜张力。我们将在定制的软基质上培养细胞，并监测Piezo 1的活性，以响应明确的机械信号和参与力产生和力传递的细胞成分的操纵。最终，我们将测试细胞表面力学如何通过青蛙胚胎中的Piezo 1控制机械信号，这对发育和病理过程具有重要意义，这些过程伴随着组织力学的变化，如神经退行性疾病。任何关于Piezo 1如何将机械信号转化为细胞内反应的见解都可能揭示药物开发的新目标，以干扰与年龄相关的问题，如痴呆症，甚至是神经损伤和神经退行性疾病后的再生过程，其中组织力学-因此Piezo 1介导的信号传导-发生变化。