Anion Carriers for Channel Replacement Therapy

常见的缩短寿命的遗传性疾病囊性纤维化（CF）的特征是跨细胞膜的阴离子转运缺陷。这项拟议中的研究旨在开发能够跨细胞膜运输阴离子的化学物质，并在安全性研究完成后准备在人类中进行测试。在英国，近11，000人患有CF，全球超过70，000人。这种疾病是由一种蛋白质，囊性纤维化跨膜传导调节因子（称为CFTR）的功能障碍引起的，该蛋白质允许阴离子（例如氯离子和碳酸氢根）穿过细胞膜。当CFTR有缺陷或从细胞膜上缺失时，体内的导管和管道就会被粘稠的粘液堵塞。在肺部，这会引发感染和炎症的恶性循环，破坏肺组织，导致呼吸困难，生活质量差和过早死亡。治疗CF根本原因的新方法是使用阴离子载体（阴离子载体）的“CFTR替代疗法”。阴离子载体是合成的小分子，其被设计为通过在膜的一侧拾取阴离子，携带它们穿过，并在远侧释放它们来取代CFTR的作用。通过吸入和插入细胞膜进入肺部后，阴离子载体可以挽救正常水平的阴离子转运，并通过一系列作用，恢复容易从肺部清除的健康粘液。在早期的工作中，我们和其他人已经表明，设计插入膜并介导跨膜阴离子转运的小分子确实是可能的。我们的一些系统能够达到非常高的活性，接近CFTR。重要的是，一些阴离子载体，与药物一样的属性，能够有效地传递到细胞膜，在那里他们工作了很长一段时间，运输阴离子进出细胞，没有毒性的迹象。根据我们以前的结果，有充分的理由相信，阴离子载体可以用来治疗CF。该项目将为实现这一目标采取关键步骤。这项工作将由布里斯托的化学家和生理学家以及澳大利亚悉尼的一个化学小组（单独资助）合作进行。最初，我们将致力于优化细胞的活动，确定最佳候选人进行更仔细的检查。然后，我们将对导管和管道内衬组织（而不是单个细胞）进行一系列测试，以验证我们的假设，即阴离子载体可以恢复CF患者的正常功能。与此同时，我们将在合成和天然膜中对阴离子载体行为进行深入研究，以便生物医学的发展可以建立在坚实的基础上。这将包括选择性和机制的调查，以及荧光显微镜，以确定阴离子载体在细胞中的分布。我们还将测试可用于帮助阴离子载体到达细胞膜的新输送系统。在项目结束时，我们将为临床研究奠定基础，可能导致CF的治疗。

The common, life-shortening inherited disease cystic fibrosis (CF) is characterised by defective anion transport across cell membranes. The proposed research aims to develop chemicals which are capable of transporting anions across cell membranes, and are ready for testing in humans after safety studies are completed.Almost 11,000 people live with CF in the UK and >70,000 worldwide. The disease is caused by malfunction of a protein, the cystic fibrosis transmembrane conductance regulator (termed CFTR), which allows the transport of anions (e.g. chloride and bicarbonate) across cell membranes. When CFTR is faulty or missing from the cell membrane, ducts and tubes in the body become blocked by thick, sticky mucus. In the lungs, this triggers a vicious cycle of infection and inflammation that destroys lung tissue, leading to breathing difficulties, poor quality of life and premature death.A novel approach to treat the root cause of CF is "CFTR replacement therapy" using anionophores (anion carriers). Anionophores are synthetic small molecules which are designed to replace the action of CFTR, by picking up anions on one side of the membrane, carrying them across, and releasing them on the far side. After their delivery to the lungs by inhalation and insertion into cell membranes, anionophores could rescue normal levels of anion transport and, through a chain of effects, restore the healthy mucus which is easily cleared from the lungs.In earlier work, we and others have shown that it is indeed possible to design small molecules which insert into membranes and mediate transmembrane anion transport. Some of our systems are capable of very high activity approaching that of CFTR. Importantly, a few anionophores, with drug-like properties, are capable of efficient delivery to cell membranes, where they work for prolonged periods, transporting anions into and out of cells, without signs of toxicity.Based on our previous results, there is good reason to believe that anionophores could be used to treat CF. This project will take critical steps towards realising this goal. The work will be performed by a collaboration involving chemists and physiologists in Bristol, and a chemistry group in Sydney, Australia (funded separately). Initially we will work towards optimising activity in cells, identifying the best candidates for closer examination. We will then apply a series of tests on tissues lining ducts and tubes (as opposed to individual cells) designed to validate our hypothesis that anionophores can restore normal function in CF patients. Meanwhile we will perform in-depth studies on anionophore behaviour, in both synthetic and natural membranes, so that biomedical development can rest on firm foundations. This will include selectivity and mechanistic investigations, as well as fluorescence microscopy to ascertain anionophore distribution in cells. We will also test new delivery systems which could be used to help anionophores reach cell membranes. At the end of the project we will have set the stage for clinical studies, potentially leading to treatments for CF.