Alice Zanella is a PhD student in Professor Walter Marcotti’s lab at the University of Sheffield. Her PhD studentship began in 2023.
Background
Age-related hearing loss is the most common sensory-related health condition in older people. It is characterised by progressive loss of hearing and decreased ability to understand speech, especially in a noisy environment. When left untreated, people can become socially isolated and prone to developing depression. Approximately half of adults in their 70’s exhibit hearing loss that is severe enough to affect communication.
One of the main features of age-related hearing loss is the loss or malfunction of extremely sensitive sound-sensing cells called hair cells, found inside a bony structure called the cochlea in the inner ear. Their name derives from the hair-like structures (called stereocilia) that project from the top of each cell.
When sound waves enter the inner ear, they cause tiny vibrations of the stereocilia. These vibrations are the first step in the conversion of sound into an electrical signal. These electrical signals are a billion times smaller than those used to charge, for example, a mobile phone. Nevertheless, these tiny signals produced by the hair cells are sent to the brain via specialized sensory nerve fibres, allowing us to perceive sound such as speech and music.
Previous research has identified age-related changes in the structure and function of hair cells which are linked to progressive hearing loss. Several are caused by changes in key genes that are important for the normal function and maintenance of stereocilia.
Aims
In this project, the student will investigate whether it is possible to use gene-based therapy to deliver normal corrected genes into malfunctioning hair cells and prevent or even rescue progressive hearing loss.
The student will try to restore normal hair cell function in mice with mutations in genes linked to age-related hearing loss, using gene therapy techniques. These techniques are safe and have been previously used in clinical trials in people of gene therapy treatments for neurodegenerative diseases.
Following the treatment, the student will use a combination of experimental approaches to measure changes in the structure and function of the hair cells and measure hearing in the mice to determine the effects on their hearing loss.
Benefit
Currently, the only options available to treat hearing loss are hearing aids and cochlear implants, which bring benefit to many people, but are unable to restore natural hearing. Thus, there is an urgent need to develop effective treatments to either prevent or slow down hearing loss or restore hearing. The results from this project will determine whether gene therapy is a suitable approach to target progressive hearing loss.