Universal cells to overcome HLA barriers in regenerative medicine

点击翻译按钮获取中文摘要

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.