Respiratory sensitisation in humans: Characterisation of pulmonary epithelial:dendritic cell interactions

我们在日常生活、家庭和工作中接触到一系列化学物质，这可能会对健康产生有害的影响。在这项研究中，我们感兴趣的是肺部对吸入的化学物质的敏感性，通常是在工作时。并不是每个人都会受到影响，但当那些受影响的人再次接触相同的化学物质时，他们可能会经历哮喘发作，他们也可能对从空气中吸入的其他制剂产生反应(这约占成人哮喘发病的10%)。这被称为呼吸道敏感化。重要的是要确定现有的或新开发的化学品是否会引起呼吸道敏感化，如果是，反应的大小。了解其中涉及的细胞机制也很重要。肺部的免疫反应是复杂的，目前还没有经过验证的测试来确定化学物质启动这些反应的可能性。动物实验经常被用来帮助进行这些评估，但它们并不总是非常准确，尽管它们确实帮助我们了解了其中的一些机制。此外，欧盟化妆品指令第7修正案(欧盟委员会，2003年)建议我们开发新的化合物测试方法，以减少动物实验。这一战略被称为3R，即在科学试验中使用动物的减少、改进和取代。这项研究的目的之一是建立避免使用人类细胞使用动物的测试方法。使用人体细胞很重要，因为它将确保开发出更具代表性的模型，用于评估这些化学物质在人体内的效力。肺中对吸入颗粒物做出反应的细胞是肺的“皮肤”、上皮细胞，以及充当真空吸尘器的细胞，这些细胞内化和中和附着在“皮肤”上的吸入物质；这些细胞被称为巨噬细胞。上皮细胞和巨噬细胞向位于肺上皮细胞下方的树突状细胞发送信息。树突状细胞还将长“探针”延伸到上皮表面，在那里它们可以直接与任何吸入的化学物质相互作用。根据收到的信息，树突状细胞然后激活免疫反应，以对抗感染和其他到达肺部的外来颗粒。然而，有时信息会出错，这是当肺部对某些类型的吸入颗粒物和化学物质变得非常敏感的时候。我们的目标是从成人肺组织中分离出细胞，这些细胞是在切除肿瘤的手术中取出的。可以使用附着在肿瘤上但不受肿瘤影响的正常肺区域。然后，我们将单独培养上皮细胞、巨噬细胞和树突状细胞，并在类似于肺的三维模型中一起培养。我们将把细胞暴露在我们知道是呼吸道敏感剂的化学物质中，以及不会导致呼吸道敏化的化学物质中，以检查与呼吸道敏化有关的细胞信息通路。我们还想确定是否存在识别化学敏感剂的独特反应，以便开发这些培养模型，并用于可能影响肺部的现有和新化合物的常规测试。此外，有了这些知识，应该有可能开发出防止这些异常反应的药物。这些模型可以用来避免使用动物来研究呼吸道敏感者，以了解呼吸道敏化的机制。

We are exposed to a range of chemicals in day-to-day life, at home and at work, which may have unwanted health effects. In this study we are interested in the sensitivity of the lung to chemicals that are inhaled, usually while at work. Not everybody is affected, but when those who are affected are exposed to the same chemical again they may experience an asthma attack, and they may also react to other agents that they inhale from the air (this accounts for approximately 10% of adult-onset asthma). This is called respiratory sensitisation. It is important to determine whether existing or newly-developed chemicals will cause respiratory sensitisation, and if so, the magnitude of the response. It is also important to understand the cellular mechanisms that are involved. The immunological responses of the lung are complex, and no validated tests exist to determine the potential of chemicals to initiate these responses. Animal experiments are often used to help make these assessments, but they are not always very accurate, although they do help us understand some of the mechanisms involved. Furthermore, the 7th Amendment to the European Union Cosmetics Directive (European Commission, 2003) recommends that we develop new ways of testing compounds so that we reduce animal experimentation. The strategy is called the 3Rs, Reduction, Refinement and Replacement of the use of animals in scientific tests. One aim of this study is to establish testing methods that avoid using animals by using human cells. Use of human cells is important as it will ensure development of a more representative model for assessing the potency of these chemicals in man. The cells in the lung that respond to inhaled particles are the lung's 'skin', epithelial cells, as well as cells that act like a vacuum cleaner, internalising and neutralising inhaled material that settles on the 'skin'; which are called macrophages. Epithelial cells and macrophages send messages to dendritic cells that sit underneath the lung epithelial cells. Dendritic cells also extend long 'probes' onto the epithelial surface where they can directly interact with any inhaled chemicals. Depending on the messages received, dendritic cells then activate the immune response to fight infection and other foreign particles that reach the lung. However, sometimes the messages go wrong, and this is when the lung becomes very sensitive to some types of inhaled particles and chemicals. We aim to isolate cells from adult human lung tissue that is removed during an operation to remove a tumour. Normal regions of lung that are attached to, but not affected by, the tumour can be used. We will then culture epithelial, macrophage and dendritic cells alone, and together in a 3-dimensional model resembling the lung. We will expose the cells to chemicals that we know are respiratory sensitisers, as well as chemicals that do not cause respiratory sensitisation, to examine the cellular messaging pathways involved in respiratory sensitisation. We also want to determine whether there are unique responses that identify chemical sensitisers so that these culture models can be developed and used for routine testing of existing and new compounds that might affect the lung. In addition, with this knowledge, it should be possible to develop drugs that prevent these abnormal responses. These models could be used to avoid the use of animals to investigate respiratory sensitisers to understand mechanisms of respiratory sensitisation.