Targeting myofibroblast mechanotransduction to prevent pulmonary fibrosis

特发性肺纤维化(IPF)是一种以肺部纤维化(疤痕形成)为特征的长期胸部疾病。这种疤痕降低了肺部吸收氧气的能力，从而使人感到呼吸困难。目前尚不清楚为什么一些人会患上IPF，但IPF患者往往进展很快就会死亡，而且没有治愈方法。这使得IPF成为一种值得研究的重要疾病。肺疤痕形成的主要特征是，由于形成疤痕组织的细胞异常高活性，肺部变得小而僵硬。这些细胞产生使肺部僵硬的蛋白质，如胶原蛋白，并收缩，使肺部变小。以前的研究表明，IPF中的肺疤痕始于肺最伸展的区域。研究还表明，当细胞在僵硬的环境中生长时，比如在有疤痕的肺内，它们会变得更加活跃，产生更多的疤痕组织。我们还知道，肺损伤会导致一种名为溶血磷脂酸(LPA)的化学物质的释放，这种化学物质会导致许多导致肺疤痕形成的事件。G蛋白是一组蛋白质，它们被细胞表面的感应分子(G蛋白偶联受体，GPCRs)“开启”，并通过激活细胞内的其他蛋白质来传递这一信息。当这个信号到达细胞核，也就是细胞的“控制中心”时，它控制着哪些基因被激活，哪些蛋白质被合成。我们知道有两个G蛋白家族(GA12/13家族和Gaq/11家族)传递导致肺瘢痕形成的信号。这两组G蛋白都可以被机械力启动，尽管我早期的实验表明这两组传递的机械力是不同的。我的早期研究结果表明，生长在“僵硬”环境中的细胞感知涉及GA12/13家族的信号，而伸展的细胞(如呼吸过程中发生的)通过Gaq/11家族传递信号，导致不同的细胞反应，这两者都会促进瘢痕形成。这个项目的目的是准确地找出GA12/13和Gaq/11家族是如何感知不同类型的机械信号(周围环境的拉伸和僵硬)和细胞损伤信号的，以及这些如何导致肺瘢痕形成。我们将比较GA12/13和Gaq/11蛋白家族对损伤、细胞伸展和基质硬度变化的反应，并与没有GA12/13或Gaq/11的细胞进行比较。我还将研究患有和不具有IPF的人的细胞是否具有不同数量的GA12/13和Gaq/11活性。此外，我将使用肺纤维化模型，在该模型中，疤痕形成细胞没有GA12/13或Gaq/11家族蛋白质，并测量这些蛋白质的缺乏如何影响肺纤维化的发展。为了在这些实验中测量疤痕形成，我将测量与肺瘢痕形成有关的重要蛋白质和基因的表达，包括胶原蛋白，以及使这些细胞更活跃(疤痕形成)的分子。我还将测量肺的硬度和为这些实验培养的细胞产生的疤痕组织。这是一种测量纤维化程度的方法，在这类研究中并不经常使用，这使得这个项目独一无二。从这些实验中，我希望更多地了解IPF如何发展以及为什么发展的原因。我将利用这些结果绘制一张地图，从细胞周围的信号开始，比如拉伸和僵硬，通过G蛋白家族，到可能导致肺疤痕的物质的产生。通过展示疤痕肺与健康组织的不同之处，我希望找出IPF发生的原因。我发现对IPF的发展很重要的分子或蛋白质也可能是新疗法的良好靶点。因此，该项目将增加我们对IPF发生原因的了解，并可能帮助我们找到IPF的治疗方法。

Idiopathic pulmonary fibrosis (IPF) is a long-term chest condition that is characterised by fibrosis (scarring) of the lungs. This scarring reduces the ability of the lungs to take in oxygen, which causes a person to feel breathless. It is not clear why some people develop IPF, but people with IPF often progress to death quickly and there is no cure. This makes IPF an important disease to research. The main feature of lung scarring is that the lungs become small and stiff due to the abnormally high activity of cells that make scar tissue. These cells produce proteins that make the lungs stiff, such as collagen, and contract, making the lungs small. Previous studies have shown that the lung scarring in IPF begins in the areas of the lung that are being stretched the most. Research has also shown that when cells grow in stiff surroundings, like that within scarred lung, they become even more active and produce more scar tissue. We also know that lung injury causes the release of a chemical called lysophosphatidic acid (LPA), which causes many events that lead to lung scarring. G proteins are a group of proteins that are "switched on" by sensing molecules on the cell surface (G protein-coupled receptors, GPCRs) and pass on this information by activating other proteins inside the cell. When this signal reaches the cell nucleus, the "control centre" of the cell, it controls which genes are switched on and which proteins are made. We know that two families of G-protein (Ga12/13 family and Gaq/11 family) pass on signals that lead to lung scarring. Both groups of G proteins can be switched on by mechanical forces, although my early experiments suggest the mechanical forces transmitted by these two groups are different. My early results suggest that cells grown in "stiff" surroundings sense signals which involve the Ga12/13 family whereas cell which are stretched (as occurs during breathing) pass signals through the Gaq/11 family, leading to different cellular responses which both promote scarring.The aim of this project is to find out precisely how the Ga12/13 and Gaq/11 families sense different types of mechanical signals (stretch and stiffness of surroundings) and cell injury signals, and how these lead to lung scarring. We will compare how the Ga12/13 and Gaq/11 protein families react to injury, cell stretch and changes in matrix stiffness with cells that don't have Ga12/13 or Gaq/11. I will also look into whether cells from people with and without IPF have different amounts of Ga12/13 and Gaq/11 activity. In addition, I will use a model of pulmonary fibrosis where the the scar producing cells do not have the Ga12/13 or Gaq/11 family of proteins and measure how the absence of these proteins affects the development of fibrosis in the lung. To measure scarring in these experiments, I will measure the expression of important proteins and genes that are involved in lung scarring, including collagen, and molecules that make these cells more active (scar forming). I will also measure both the stiffness of the lung and the scar tissue made by the cells grown for these experiments. This is a method of measuring the level of fibrosis not often used in this kind of research, making this project unique. From these experiments, I hope to learn more about the reasons behind how and why IPF develops. I will use the results to draw a map starting with the signals from the cell's surroundings, such as stretch and stiffness, through the G protein families, to the production of the substances that may cause lung scarring. By showing how these differ in scarred lung compared with healthy tissue, I hope to find out why IPF develops. The molecules or proteins that I find to be important for the development of IPF may also be good targets for new treatments. Therefore, this project will increase what we know about why IPF develops, and may help us to find a cure for IPF.