Defining regional anatomical variation in cellular composition, transcriptome and epigenome in the human kidney

肾脏在清洁血液和控制身体水分平衡方面起着至关重要的作用。不幸的是，它们的功能可能会受到一些常见疾病的影响，包括感染、糖尿病、血液供应减少和高血压造成的损害，或者一些药物的毒性作用。肾衰竭可以通过透析或移植治疗，但两者(特别是透析)都与预期寿命缩短有关。肾脏的各个组成部分被称为细胞，每个肾脏都有数以亿计的细胞，这些细胞以类似的功能分组工作。单个细胞和细胞组的相互作用是正常器官功能所必需的。驻留在肾脏中的不同类型的细胞包括免疫细胞，即人体防御系统细胞。这些哨兵站岗，通过启动炎症反应提醒身体注意局部问题。它们在组织愈合和修复中也发挥着重要作用。由于排泄废物和控制水分平衡的工作，肾脏为免疫细胞创造了一个不寻常和困难的环境；肾脏的某些部分盐分浓度非常高，因此细胞生活在盐沼中，这可能会影响它们的功能。目前，我们还不完全了解构成肾脏的不同类型的细胞，有多少不同的免疫细胞生活在那里，它们彼此之间的位置如何，或者肾脏某些部分的极端环境是否会改变细胞的行为。回答这些问题将有助于我们确定肾脏疾病中细胞功能是如何出错的，因此将有助于开发更好的治疗方法。我们的目标是绘制人类肾脏的细胞图谱。我们将采取两种实验方法：第一种方法是取一块肾脏，将其捣碎以分解细胞组，这样我们就可以分析单个细胞。不同的细胞有不同的功能和识别标记，因为它们的遗传物质(称为基因)的部分翻译成蛋白质的方式不同。蛋白质是标记细胞并使其发挥功能的分子。每个细胞都含有数以万计的蛋白质，这赋予了它独特的特征，但这些蛋白质很难在单个细胞中进行测量。然而，我们可以测量在基因和蛋白质之间起中介作用的分子，这被称为信使RNA或mRNA。在过去的10年里，技术已经进步到我们可以在单个细胞中测量数千个mRNA分子，这就是我们计划对从人类肾脏的6个不同区域采集的碎状肾脏样本所做的事情。我们的第二个实验方法是提取一块肾脏并保持其完好无损，以便维持太空中细胞的关系。然后，我们将把这块肾脏切片，这样它们就足够薄，可以在显微镜下看到。我们将使用第一个实验中的信使核糖核酸信息来识别少数标记，这些标记可以通过使用荧光标记的探针在显微镜下可视化。这将使我们能够调查细胞之间的相对位置，以及成年肾脏和发育中的肾脏中的不同细胞如何为免疫细胞提供支持或“利基”。绘制正常肾脏细胞的完整图谱将提供关键的参考图谱，有助于研究人员在未来了解不同肾脏疾病中哪些细胞变得异常，以及疾病中细胞相互作用是如何中断的。这将为帮助确定新的治疗靶点提供宝贵的信息。

The kidneys play a vital role in cleaning the blood and controlling the body's water balance. Unfortunately, their function may be affected by a number of common diseases including infection, diabetes, damage by reduced blood supply and high blood pressure or the toxic effects of some drugs. Kidney failure can be treated with dialysis or transplant, but both (particularly dialysis) are associated with reduced life expectancy. The individual building blocks of the kidneys are called cells, and each kidney has hundreds of millions of cells that work in groups that have a similar function. The interaction of individual cells, and groups of cells, is required for normal organ function. Among the different cell types that reside in the kidney are immune cells, the body's defence system cells. These sentinels stand guard and alert the body to local problems by starting an inflammatory response. They also play an important role in tissue healing and repair. Because of their job of excreting waste and controlling water balance, the kidneys make an unusual and difficult environment for immune cells; some parts of the kidney have a very high salt concentration, so the cells are living in a salt marsh and this can affect their function. At present, we don't fully understand the different types of cells that make up the kidney, how many different of immune cells live there, how they are positioned relative to each other, or whether the extreme environment of some parts of the kidney changes how the cells behave. Answering these questions will help us to determine how cell function goes wrong in kidney diseases and will therefore allow the development of better treatments.Our aim is to make a cell map of the human kidney. We will take two experimental approaches: The first is to take a piece of kidney, mash it up to break up the cell groups so that we can analyse individual cells. Different cells have different functions and identification marks because of differences in which parts of their genetic material (called genes) are translated into proteins. Protein are the molecules that mark a cell and allow it to function. Every cell contains tens of thousands of proteins, giving it a unique signature, but these are hard to measure in a single cell. However, we can measure the molecule that acts as an intermediate between genes and proteins, this is called messenger RNA or mRNA. In the past 10 years, technology has advanced such that we can measure thousands of mRNA molecules in a single cell, this is what we plan to do with the mashed kidney samples that we will take from 6 different regions across the human kidney.Our second experimental approach is to take a piece of kidney and keep it intact so that the relationship of the cells in space is maintained. We will then make slices of the piece of kidney so that they are thin enough to be seen under a microscope. We will use the mRNA information from our first experiment to identify a small number of markers that can be visualised by the microscope using probes that are fluorescently labeled. This will allow us to investigate the position of cells relative to each other and how different cells in both the adult and developing kidney provide support or a 'niche' for immune cells.Making a complete map of cells in the normal kidney will provide a critical reference atlas that will help researchers in the future to understand which cells become abnormal in different kidney diseases and how cell interactions are disrupted in disease. This will provide invaluable information to help identify new treatment targets.