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Protecting hearing from environmental stress
The aim of the project is to bring protection from age-related hearing loss a step closer.
People lose their hearing as they get older because the sensory hair cells that are responsible for detecting sound die and are not replaced. One of the reasons sensory cells are thought to die is because of the damage accumulated by a lifetime of exposure to environmental stressors, such as noise and toxins. However, the good news is that some people are able to keep their hair cells and hearing into very old age, so mechanisms for preventing damage must exist. Currently, we know little about these protective mechanisms.
The research team has identified a gene called caprin-1 that they suspect is involved in the response of hair cells to severe stress. The experiments planned for the project will test whether or not that is the case. Starting this month, the team will manipulate the amount of this gene that is present in the hair cells to see if they become better able to survive damage that we know can kill the cells.
These experiments involve producing a virus which will deliver the gene to the hair cell in a laboratory dish. The method will exploit the ability that viruses have evolved to insert parts of their DNA in the cells of other organisms. The researchers will hijack the process by substituting DNA from the virus with caprin-1.
There are only a few laboratories in the world that are able to generate and use viruses in this way in the inner ear. So as part of the project, Dr Emily Towers, a scientist working with the UK team, will visit Dr Jeff Holt’s lab at the University of Virginia, USA to learn how to use the virus technology.
Dr Towers says: “To better understand the function of different genes involved in hair cell survival it is critical to be able to alter gene expression in cell models. This has proved very difficult to do in hair cells and viral delivery is one of the few ways that has resulted in good levels of success, but only in a few hands. Success is dependent on the type of virus used as well as the production methods. Dr Holt's laboratory has a proven track record in using viruses to manipulate gene expression in hair cells, a technique I hope to learn and bring back to the UCL Ear Institute to further our research on the role of caprin-1 in hair cell survival."
Dr Towers will then return to the UK to use the technology to investigate the stress response in hair cells. Identifying the molecular mechanisms involved in protecting cells during damage will contribute to future work aimed at boosting such mechanisms in people who are beginning to lose their hearing.
