Are the pathways that protect tissues from mechanical stress lost in ageing?

我们细胞的决定性品质——它们的物理特征和功能——可以由它们的环境决定，但组织环境可能是苛刻的。就像我们的肌肉再生并通过锻炼来保持健康一样，我们的细胞也发展出了防止机械应力引起的损伤的机制。对压力的基本反应是我们细胞内伴侣蛋白的产生。这些分子机器通过将被压力解开的蛋白质重新折叠成功能结构来限制和逆转损伤。然而，这些机制被认为会随着年龄的增长而退化。这种功能的丧失可能会因其他影响组织老化的因素而加剧。细胞外基质——细胞嵌入其中的物质——可能会在老化的组织中变硬并变成纤维，从而改变组织内细胞承受机械压力的方式。因此，了解细胞感知和响应物理信号的途径是理解衰老过程的关键。该项目将研究作为衰老模型的衰老细胞如何在二维和三维环境中对周期性紧张作出反应。它将建立在Swift实验室令人兴奋的新发现的基础上：(1)衰老细胞失去了“感觉”和对环境机械特性做出反应的能力；（ii）衰老细胞在面临压力时也失去表达保护性伴侣蛋白的能力；（iii）机械敏感性和伴侣表达的调节是健康（即非衰老）细胞应变反应的组成部分。衰老细胞的反应将与对照细胞进行比较，使用以下组合：显微镜，以表征细胞内的结构和形态变化；质谱蛋白质组学，以公正的方式确定衰老过程中取消的应激调节途径；和RNA-Seq转录组学来建立完整的信号通路。我们还将寻找细胞完整性受损的证据，例如DNA损伤的累积。通过敲除关键蛋白，或通过表达衰老细胞中的蛋白质来恢复功能，将对重要的途径进行更详细的研究。这个“基础生物科学”项目将采用多学科方法，为机械负荷组织的衰老过程提供基本见解。它的目标是从分子水平到它们在三维环境中复制活跃的活组织的整合，构建细胞功能的整体图景。该项目将以两种方式履行BBSRC的ENWW职责：首先，它将建立在Swift实验室在将复杂的“组学”数据集与成像和分子生物学方法相结合方面的经验之上，以全面了解潜在的生物学。该学生将使用质谱分析、蛋白质组学和RNA-Seq分析样品（在Core Facilities的支持下），并将在具有生物信息学和统计学背景的成熟合作者的帮助下解释数据。其次，这是一个跨学科的项目，结合了分子和细胞生物学与生物物理学的方法，以建立对生理衰老过程的更好理解。学生将有机会在生物、物理和工程实验室使用广泛的工具。他们将学习如何以新颖的方式解决问题，并将很好地利用学科之间重叠的令人兴奋和未开发的领域。

The defining qualities of our cells - their physical features and function - can be determined by their surroundings, but the tissue environment can be demanding. Just as our muscles regenerate and are conditioned by exercise to maintain health, our cells have developed mechanisms to protect against damage induced by mechanical stress. A fundamental response to stress is the production of chaperone proteins within our cells. These molecular machines act to limit and reverse damage by refolding the proteins unwound by stress back into functional structures. However, these mechanisms are thought to deteriorate as we age. This loss of function may be compounded by other factors affecting ageing tissue. The extracellular matrix - the material in which cells are embedded - may stiffen and become fibrotic in ageing tissue, changing the ways that tissue-resident cells experience mechanical stresses. A knowledge of the pathways that enable cells to sense and respond to physical signals is therefore key to understanding the ageing process. This project will look at how senescent cells, used as a model of ageing, respond to periods of cyclic straining in two- and three-dimensional environments. It will build on new and exciting findings from the Swift laboratory: (i) that senescent cells lose their ability to 'feel' and respond to the mechanical properties of their environments; (ii) that senescent cells also lose their ability to express protective chaperone proteins when faced with stress; and (iii) that regulation of mechano-sensitivity and chaperone expression are integral to the strain response in healthy (i.e. nonsenescent) cells. The responses of senescent cells will be compared to control cells using combinations of: microscopy, to characterise structural and morphological changes within cells; mass spectrometry proteomics, to identify, in an unbiased way, the stress-regulation pathways abrogated in senescence; and RNA-Seq transcriptomics to establish complete signalling pathways. We will also look for evidence of compromised cellular integrity, such as the accruement of DNA damage. Important pathways will be investigated in more detail by knocking down key proteins, or by expressing proteins in senescent cells to restore function. This 'Underpinning Bioscience' project will take a multidisciplinary approach to deliver fundamental insight into the ageing process in mechanically loaded tissues. It will aim to build a holistic picture of how cells function, from a molecular level to their integration within three-dimensional environments that replicate active, living tissues. The project will deliver on the BBSRC's ENWW remit in two ways: Firstly, it will build on the Swift lab's experience in integrating complex '-omics' datasets with imaging and molecular biology methods to give a complete understanding of the underlying biology. The student will analyse samples using mass spectrometry proteomics and RNA-Seq (with support from Core Facilities), and will interpret the data with assistance from established collaborators with backgrounds in bioinformatics and statistics. Secondly, it is very much an interdisciplinary project that combines methods in molecular and cell biology with biophysics to build an improved understanding of the physiological ageing process. The student will have access to a broad range of tools in biology, physics and engineering laboratories. They will learn how to solve problems in novel ways and will be well placed to take advantage of the exciting and underexploited areas of overlap between disciplines.