How does blocking inflammation enhance human cutaneous immunity during ageing in vivo?

虽然动物模型已经被用来研究衰老过程中免疫功能下降的机制，但在动物和人类之间进行直接比较之前，寿命的差异和物种的特定差异。此外，大多数人体研究都是在从血液中分离出来的白细胞上进行的，这些白细胞可能无法反映组织中免疫反应期间发生的事件，这类似于说在高速公路上行驶的人代表了生活在高速公路服务的大城市的人。我们开发了一种新的方法来研究人体组织中免疫反应期间的白细胞。通过这些新方法，我们试图了解为什么老年人对皮肤中本应免疫的病原体反应很差，比如水痘病毒。这也可以解释为什么老年人患皮肤癌的几率更高，皮肤感染的几率也更高。在之前的一项研究中，我们有一个相当令人惊讶的发现，老年人对水痘病毒的反应减弱并不是因为与年轻受试者相比，识别这种病毒的白细胞数量减少，无论是血液还是皮肤。相反，这种反应的降低是由于皮肤环境本身的变化，在那里我们发现了更多的背景炎症。我们在之前的研究中所做的是减少老年志愿者的炎症，使用葛兰素史克(GSK)的一种抗炎药物，看看这是否可以增强他们对水痘病毒的皮肤反应。简而言之，我们能够做到这一点，我们已经发表了这项工作。然而，关键问题仍然没有得到回答，包括确定炎症最初是从哪里来的，即皮肤中的哪些细胞制造了炎症？哪些细胞分泌蛋白质将炎性白细胞(称为单核细胞)招募到皮肤？最后，这些单核细胞如何在衰老过程中抑制免疫反应？它们是单独工作还是与其他类型的细胞一起工作？我们将从皮肤中取出单独的细胞，并观察它们的基因表达，看看哪种类型的细胞产生炎症蛋白。我们将与剑桥大学的梅纳·克拉特沃西教授一起进行这一部分的研究，他已经使用这些技术对人体组织进行了极其重要的研究。我们还将确定哪些细胞分泌将炎性单核细胞从血液中吸引到老年人皮肤中的分子。与纽卡斯尔的Muzlifah Haniffa教授合作，我们将能够开始生成老年人不同皮肤细胞的基因组图谱，以便与她已经分析过的年轻人进行比较。此外，我们将与类风湿关节炎患者关节炎症专家克里斯·巴克利教授合作，研究皮肤中称为成纤维细胞的细胞是否像关节一样参与其中。我们的初步结果表明，这种可能性是可能的，我们设想了不同细胞类型之间可能的相互作用，以诱导我们在老年人皮肤中观察到的炎症。这将通过我们将与克拉特沃西教授一起进行的单细胞RNAseq分析来解决。下一个问题是炎症是如何阻止皮肤中常驻白细胞的功能的。我们将测试是否由于罪魁祸首细胞分泌因子的直接抑制作用，是否炎症使其他细胞踩刹车抑制免疫力，或者炎症是否召唤了被称为调节细胞的“军事警察”，以使皮肤中的一切平静下来。最后，我们将使用我们在之前的一项研究中产生的生物库样本来探索如何在旧的工作中抑制炎症-它是否阻止炎性单核细胞的招募？阻止抑制性细胞的产生或阻止不同类型细胞之间的相互作用，破坏它们之间的协同作用，从而扑灭炎症的火。

Although animal models have been used to investigate mechanisms for immune decline during ageing, differences in lifespan and species specific differences prelude direct comparison between animals and humans. Furthermore, most human studies are conducted on white cells isolated from the blood that may not reflect on events that take place during an immune response in the tissues, akin to saying that people travelling on a motorway are representative of the people living in big cities served by the motorway. We developed a new way of investigating white cells in human tissues during an immune response. With these new methods we are trying to understand why older humans respond badly to pathogens in the skin that they should be immune to, like the chickenpox virus. This may also explain why older individuals get more skin cancer and also more skin infections. In a previous study we made a rather surprising finding that the reduced response to the chickenpox virus in old people was not due to a decrease in the number of white cells that recognize this virus as compared to young subjects in either the blood or the skin. Instead this decreased response was due to changes in the skin environment itself, where we identified more background inflammation. What we did in this previous study was to reduce the inflammation in old volunteers, using an anti-inflammatory drug from Glaxo-Smith-Kline (GSK) to see if this could enhance their response in the skin to the chickenpox virus. In a nutshell, we were able to do so and we have published this work. However key questions remained unanswered including identifying where the inflammation was coming from in the first place i.e. which cells in the skin were making it? Which cells secreted proteins to recruit inflammatory white blood cells, called monocytes, to the skin? Finally how do these monocytes contribute to the inhibition of the immune response during ageing? Do they work alone or together with other cell types?We will take individual cells out of the skin and look at their gene expression to see which cell type makes the inflammatory proteins. We will do this part of the study with Professor Menna Clatworthy in Cambridge University who has already performed extremely important studies on human tissue using these techniques. We will also determine which cells secrete the molecules that attract inflammatory monocytes from the blood into the skin of older subjects. In collaboration with Professor Muzlifah Haniffa in Newcastle we will be able to begin to generate a genomic map of different skin cells from old people for comparison with young individuals that she has already analysed. Furthermore in collaboration with Prof. Chris Buckley who is an expert on inflammation in joints in patient with Rheumatoid Arthritis, we will investigate if cells called fibroblasts in the skin are involved, like they are in the joints. This possibility is suggested by our preliminary results and we envisage possible interactions between different cell types to induce the inflammation we observe in the skin of older humans. This will be addressed with the single cell RNAseq analyses that we will perform with Prof. Clatworthy. The next question is how the inflammation blocks the function of the resident white cells in the skin. We will test if it is due to a direct inhibitory effect of secreted factors from the culprit cell, if the inflammation makes other cells turn on the brakes to inhibit immunity or if the inflammation calls in the "military police" known as regulatory cells that calms everything down in the skin. Finally we will used bio-banked samples that we generated in a previous study to probe how inhibiting inflammation in the old works -does it prevent recruitment of inflammatory monocytes? Prevent the generation of inhibitory cells or stop the interaction between different cell types, breaking the synergy between them and thus puts out the fire of inflammation.