Universal cells to overcome HLA barriers in regenerative medicine

在英国，超过6400人正在等待实体器官移植，其中一个主要问题是需要匹配捐赠者和接受者，以防止免疫系统的排斥反应。最近的发展表明，‘基因组编辑’可能会让我们生产出‘通用’干细胞，用来修复或再生患病的器官。我们对将这项技术应用于多能干细胞感兴趣，然后这些干细胞可以用来产生许多不同类型的组织。这一过程涉及使用名为CRISPR-Cas9的工具来改变细胞的DNA，使免疫系统看不到细胞。这是通过扰乱细胞中的DNA代码来实现的，细胞中的DNA代码产生了称为人类白细胞抗原(HLA)的表面分子。这就像是将细胞识别为宿主或自身的“标志”，每个细胞可以显示多达12个来自两个不同类别或结构的不同的非常不同的标志。该项目将测试移除这些标志的策略。如果免疫系统警觉到所有的标志都丢失了，那么可能有必要用一个‘中性’标志来代替它们。我们将比较不同的方法来高效和安全地制造“通用细胞”，然后在再生医学中心已经在进行的项目中进行测试。如果出现不想要的副作用，还将包括一个安全基因，以便在必要时移除细胞。我们将分四个阶段交付该项目，第一阶段的大部分将在伦敦大学学院和加州大学进行。在最后一年，英国皇家骑警在爱丁堡和剑桥的枢纽也参与了进来。设想了四个“工作包”：1.开发和测试分子工具，这些工具将用于切割和编辑DNA，这些DNA编码细胞上的“标志”2。测试和培养人类干细胞，这些干细胞以后可以用来产生大量的肝细胞或免疫细胞，帮助清理细胞碎片。在(1)中开发的工具将被用来在实验室中修改这些干细胞，以查看它们是否可以通用。3.应用最先进的测序和计算机建模来检查干细胞是否在目标基因以外的基因位置进行了修改。测试是否包含“安全”开关，以防细胞产生副作用或感染病毒。对通用干细胞进行测试，看看它们是否可以逃避小鼠的免疫反应。到项目结束时，我们预计能够生产出“通用的”多能干细胞，然后可以在早期临床试验中应用于各种应用。

Over 6400 people are waiting for solid organ transplants in the UK and one major issue is the need to match donors and recipients to prevent the immune system rejection. Recent developments suggest that 'genome editing' might allow us to produce 'universal' stem cells that can be used to repair or regenerated diseased organs. We are interested in applying the technology to pluripotent stem cells that could then be used to generate many different types of tissue. The process involves using tools called CRISPR-Cas9 to change the cells' DNA to make them cells invisible to the immune system. This is done by disrupting the DNA code in cells that produces surface molecules called human leukocyte antigens (HLA). These are like 'flags' that identify cells as host or 'self' and each cell can display up to 12 different very different flags from two different classes or structures.The project will tests strategies to remove the flags. It may be neccessary to replace them with a single 'neutral' flag in case the immune system becomes alarmed that all the flags are missing. We will compare different routes to efficiently and safely manufacture 'universal cells' which will then be tested in projects already underway in the regenerative medicine hubs. In case of unwanted side effects, a safety gene will also be included to allow cells to be removed if necessary.We will deliver the project in four stages with the bulk of the first stages to be undertaken at UCL and UoC. There is additional involvement of UKRMP hubs in Edinburgh and Cambridge in the final year. Four 'work packages are envisaged:1. To develop and test the molecular tools that will be used to cut and edit DNA that codes for 'flags' on cells2. Test and grow human 'stem' cells that can be later used to produce large numbers of liver cells or immune cells that help clean up cell debris. The tools developed in (1) will be used to modify these stem cells in the lab to see if they can be made 'universal' 3. Apply state of the art sequencing and computer modelling to check if the stem cells have been modified at gene sites other than those being targeted.4. Testing the inclusion of a 'safety' switch in case cells cause side effects or get infected with viruses.5. Testing of universal stem cells to see if they can evade immune responses in mice.By the end of the project, we anticipate being in a position to be able to produce 'universal' pluripotent stem cells that could then be applied to various applications in early stage clinical trials.