Stem Cell Medicine Research Group
There are currently many incurable childhood diseases, and stem cell approaches offer significant promise towards developing new therapies for these conditions. The stem cell field of research has developed considerably in the last few years with the advent of iPS cells. These are stem cells which are generated from tissues of children or adults, including blood and skin cells. We can then direct the iPS cells to turn into cells that can form tissue and mini-organ structures ("organoids") in the laboratory dish, a process biologists called "differentiation", so they can be used in studies.
This technology provides us with an opportunity to study tissues derived from a patient’s own cells. We have developed differentiation methods to generate retinal and inner ear organoids from iPS cells. We work with organoids as they replicate aspects of normal development and provide unlimited quantities of cells for research. Organoids are also amenable to molecular and imaging approaches.
Our group's main areas of research involve the differentiation of human iPS cells into retinal and inner ear organoids to understand the development of the human retina and to model diseases.
Understanding human retinogenesis
In the lab, we are interested in using our 3D retinal organoids to understand human retinal development. Of particular interest is the development of cone photoreceptor cells and the events leading to the formation of the cone-rich macular region in humans. Embryonic retinogenesis takes place in a three-dimensional environment, where various cellular, molecular, and electrophysiological cues are spatially and temporally coordinated. More than likely, many of these cues are missing from our current in vitro system. Adding cultures with molecular, electrical, and light-evoked cues to the cultures may increase the utility of the in vitro system in dissecting the detailed events in human retinogenesis.
Modelling of retinal and otic degenerative diseases
Relatively little is known about why photoreceptor and hair cells die in many different degenerative conditions. We seek to understand the mechanisms underlying diseases of the retina and ear as well as develop therapeutic approaches that will slow or prevent the loss of degenerative cells. The approaches we are using include gene therapy and gene editing technologies.
Usher (USH) syndrome
Our projects in this area aim to investigate the pathophysiology of USH syndrome using iPS cells and thus improve our understanding of USH syndrome. Mutations in over 13 genes have been identified to cause USH, especially affecting sensory hair cells and photoreceptors in the inner ear and retina, respectively. The lack of animal models that faithfully replicate the human pathology means that little is known about its pathophysiology and the mechanism of cellular degeneration, hindering the development of new therapies. Currently no treatments are available for the retinal defect and only a limited number of the patients can benefit from cochlear implants. Hair and photoreceptor sensory cells share common structural features, such as cilia and ribbon synapses, and the USH syndromes can therefore be regarded as diseases of cilia ("ciliopathies").
The main objectives of our research are to characterise both retinal and inner ear USH iPS-derived organoids to investigate disease physiology and most importantly to develop new therapeutic approaches, such as gene therapies.