How does the desmosome-actin crosstalk regulate desmosome function?

桥粒-肌动蛋白串扰如何调节桥粒功能？

• 批准号: BB/X008827/1
• 负责人: Christoph Ballestrem
• 金额: $ 70.64万
• 依托单位: University of Manchester
• 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%2FX008827%2F1
• 关键词: How; does; desmosome; actin; crosstalk

Cells in stress-exposed tissues, e.g. heart muscle and coverings of body surfaces, are bound together by tiny structures called desmosomes, aberrant function of which causes diseases such as heart failure, defective wound healing, cancer spread and blistering diseases of the skin and oral cavity. Desmosomes are also important for normal development, where they stabilise developing tissues. It is therefore essential to understand how desmosome function is regulated.We have shown that an important factor contributing to tissue toughness is that the ability of desmosomes to adopt a highly adhesive state known as hyper-adhesion. Hyper-adhesion is important for tissue strength, but also locks cells together restricting their movement. During wound healing, epidermal cells migrate to close the wound. The invasive spread of cancer cells also requires cell migration and in development cell movement generates the correct architecture of tissues. When cells move and grow to establish cell sheets, they form new desmosomes that mature to become highly adhesive. When cell sheets are wounded they rapidly lose hyper-adhesion and downregulate desmosomes by internalising them. Little is known about how desmosomes assemble, change their adhesive state and how they are downregulated when this is needed.Desmosomes have a characteristic structure made up of a few components and we have found that most of these components are stably integrated into the structure. However, one of them, called plakophilin (Pkp), moves rapidly from the periphery to central parts of the cell and vice versa. We think that this dynamic behaviour serves to transmit information (signals) within the cell and leads to changes in cell behaviour. Normally desmosomes appear at the junctions between cells but studies have shown whole desmosome inside cells, as though one cell has "eaten" the desmosome! We have now induced cell separation in culture and shown that they do indeed engulf whole desmosomes. This is exciting because it enables us to investigate the mechanism behind a process that occurs in normal and diseased tissues.Desmosome engulfment resembles a process called phagocytosis whereby cells of the immune system engulf extracellular particles, e.g. bacteria. Phagocytosis requires active contractile activity by the engulfing cell so as to surround the particle and draw it inside. Such contractility requires the action depends upon filamentous proteins called actin and myosin, similar to those involved in muscle contraction. Functional actin and associated proteins are also important for desmosome regulation. Desmosomes are normally internally linked to other filaments called intermediate filaments (IF), rather than actin. Desmosomes link IF from cell-to-cell by, forming a scaffolding that gives strength to tissues. However, IF possess nor contractile activity Hence the question that arises of how actins link up to desmosome to regulate their function when contractility is required? We have pilot data showing that a number of proteins known to interact with actin are very close to desmosomes and we think that these are involved in regulation of desmosome adhesion and engulfment. Our data also suggest that the actin cytoskeleton influences signalling by Pkp. We will use state-of the-art microscopy to study how desmosomes become associated with the contractile machinery as they assemble and switch from hyper-adhesion to engulfment, and mass spectrometry to identify how actin binding proteins are involved in regulating desmosome function. Finally, we will use molecular cell biology to determine the role Pkp in this process and in signalling cell behaviour. Our results will both further our understanding of normal development and provide a basis for new therapies for major health problems such as chronic wounds, some types of heart failure, skin blistering diseases and, potentially, for limiting the spread of cancer.

暴露于压力的组织中的细胞，例如心肌和身体表面的覆盖物通过称为桥粒的微小结构结合在一起，桥粒的功能异常会导致心力衰竭、伤口愈合不良、癌症扩散以及皮肤和口腔起泡疾病等疾病。桥粒对于正常发育也很重要，它们可以稳定发育中的组织。因此，有必要了解桥粒功能是如何调节的。我们已经证明，影响组织韧性的一个重要因素是桥粒采取高度粘附状态（称为超粘附）的能力。超粘附对于组织强度很重要，但也会将细胞锁定在一起，限制其运动。在伤口愈合过程中，表皮细胞迁移以闭合伤口。癌细胞的侵袭性扩散也需要细胞迁移，并且在发育过程中，细胞运动产生正确的组织结构。当细胞移动并生长以形成细胞片时，它们会形成新的桥粒，这些桥粒成熟后变得高度粘附。当细胞片层受伤时，它们会迅速失去超粘附力，并通过内化桥粒来下调桥粒。关于桥粒如何组装、改变其粘附状态以及在需要时如何下调它们知之甚少。桥粒具有由几个组件组成的特征结构，我们发现这些组件中的大多数都稳定地整合到该结构中。然而，其中一种称为 plakophilin (Pkp) 的物质可以从细胞的外围快速移动到中心部分，反之亦然。我们认为这种动态行为有助于在细胞内传输信息（信号）并导致细胞行为的变化。通常桥粒出现在细胞之间的连接处，但研究表明整个桥粒位于细胞内，就好像一个细胞“吃掉”了桥粒一样！我们现在已经在培养物中诱导细胞分离，并表明它们确实吞噬了整个桥粒。这是令人兴奋的，因为它使我们能够研究正常和患病组织中发生的过程背后的机制。桥粒吞噬类似于一种称为吞噬作用的过程，免疫系统的细胞吞噬细胞外颗粒，例如细胞外颗粒。细菌。吞噬作用需要吞噬细胞的主动收缩活动，以包围颗粒并将其吸入内部。这种收缩性需要依赖于称为肌动蛋白和肌球蛋白的丝状蛋白，类似于那些参与肌肉收缩的丝状蛋白。功能性肌动蛋白和相关蛋白对于桥粒调节也很重要。桥粒通常在内部连接到称为中间丝 (IF) 的其他丝，而不是肌动蛋白。桥粒通过形成支架将细胞间的 IF 连接起来，为组织提供强度。然而，IF 不具有收缩活性，因此，当需要收缩性时，肌动蛋白如何连接桥粒来调节其功能？我们的试验数据显示，许多已知与肌动蛋白相互作用的蛋白质非常接近桥粒，我们认为这些蛋白质参与桥粒粘附和吞噬的调节。我们的数据还表明肌动蛋白细胞骨架影响 Pkp 信号传导。我们将使用最先进的显微镜来研究桥粒在组装并从超粘附转变为吞噬时如何与收缩机制相关联，并使用质谱法来确定肌动蛋白结合蛋白如何参与调节桥粒功能。最后，我们将利用分子细胞生物学来确定 Pkp 在此过程和信号传导细胞行为中的作用。我们的研究结果将进一步加深我们对正常发育的理解，并为慢性伤口、某些类型的心力衰竭、皮肤水泡疾病等重大健康问题的新疗法提供基础，并有可能限制癌症的扩散。