Gene regulation, genetic mechanisms and development of potential therapies for corneal endothelial dystrophies

Background and need for the research: The cornea is the transparent window situated at the front of the eye. It protects the eye from the external environment and focuses light onto the retina. The inner most part of this tissue is comprised of a specialised layer of corneal endothelial cells. These cells perform a pump-like mechanism removing water from the outer layers of the cornea, to ensure that the tissue is optimally hydrated, and regulate the movement of crucial nutrients into the rest of the cornea. The term 'corneal endothelial dystrophies (CEDs)' describes a group of diseases that lead to dysfunction of this specialised cellular layer. Patients with CEDs experience corneal swelling and clouding, due to endothelial cell dysfunction, leading to impaired vision. In some patients, glaucoma develops, that further increases the likelihood of visual impairment and/or blindness.

Fuchs endothelial corneal dystrophy (FECD) is an age-related disease and by far the most common CED, affecting 4.5% of people >50 years of age. Other much rarer types of CEDs include a disorder called posterior polymorphous corneal dystrophy (PPCD). In recent years, there has been much progress in understanding the genetic causes of CEDs and we now know certain genetic faults, known as mutations, in several different genes are responsible for disease. However, we still do not fully understand the underlying biological basis of these diseases, and >20% of cases still remain genetically unexplained. Corneal transplantation is currently the only treatment option available for CED patients experiencing visual loss, but the long-term survival of grafts is poor. Surgery also relies upon specialist facilities and healthy donor corneas, of which there is a currently a global shortage. Only by understanding how the mutations alter the normal functioning of the corneal endothelium, can appropriate new therapeutic strategies be developed to address the urgent clinical need for alternative treatment options.

Aim: This research program aims to 1) identify the genetic cause of disease in unsolved CED cases and 2) investigate how and why different CED-associated mutations cause endothelial cell dysfunction and 3) use this knowledge to develop new therapies.

Methods: DNA samples from CED patients will be analysed using a range of genetic sequencing methods to identify genetic origins of disease. In parallel, using donated tissue removed during planned corneal transplant surgery, I will use techniques that I have established in the laboratory to grow and maintain the corneal endothelial cells, to enable investigation of how and why particular mutations cause cellular dysfunction and disease. This knowledge will be harnessed to design gene-directed treatment strategies. Endothelial cell cultures established from diseased patients tissue will act as the ideal model system to test the efficacy of different treatment strategies in a safe and disease relevant context.

Expected outcomes of the study: This study will identify genetic causes of CEDs that will in the short term facilitate earlier pre-symptomatic detection of disease in affected families, inform genetic counselling and may alter the clinical management of disease. In parallel, cellular mechanisms of corneal disease will be investigated to enhance understanding of the biological reasons for disease to enable effective non-surgical treatments to be developed for these sight threatening conditions. Knowledge gained will also impact upon the areas of personalised medicine, age-related disease, and human genetics.

The primary goal of my research is to understand the genetic causes and underlying pathogenic mechanisms that are responsible for inherited corneal endothelial dystrophies (CEDs) so that this knowledge can be translated into improved clinical care including earlier detection (genetic and clinical) and improved treatment strategies and outcomes.

In the UK life expectancy has increased by approximately 30 years over the past century and therefore age-related conditions such as FECD (the most common CED) are consequently placing an ever-increasing burden on the healthcare system. Hence, there is ever growing demand for innovative (donor tissue independent) and preventative therapies to address this global healthcare need.
This overall research program has broad reaching impact to the recipients based in the UK and beyond and will specifically benefit the following:

- Research scientists in academia who are aiming to gain a better understanding of corneal biology and genetics, ophthalmology, age-related disease mechanisms, non-coding mutation discovery and their molecular consequences, repeat-expansion mediated diseases aetiology and genomic medicine.

- Biomedical scientists in academia and industry who are endeavouring to understand the molecular mechanisms of ophthalmic, triplet repeat-mediated and/or age-related diseases and how this knowledge can be harnessed for therapeutic intervention.

- Medical practitioners, ophthalmologists and clinical geneticists who are treating corneal endothelial dystrophy (CED) patients and of course the affected patients themselves and their respective family members will all benefit from this research. Data generated will aid and advise molecular diagnostic procedure, impact on the clinical management of disease, facilitate earlier pre-symptomatic detection of disease in families and improve genetic counselling for this patient group.

- The UK economy will benefit from this research proposal through biotech and pharmaceutical innovation conducted within the UK. For example, this research program and the groups scientific and clinical expertise biotech will favour Biotech companies such as ProQR to conduct clinical trials at UK based hospital such as Moorfields. Furthermore, treatments developed as part of this research program have the potential to prolong patients' ability to maintain their employment status.

- Healthcare policy makers will be influenced by knowledge acquired and new diagnostic methods and therapies devised as a direct outcome of this research program leading to improved public health in the UK and beyond.

-Public sector organisations will benefit and be influenced by scientific progress made by award. For example. UK-based eye charities including Fight for Sight, Moorfields Eye Charity and the National Eye Research Centre, who have seed funded different elements of this research program will collectively benefit from the ongoing success and outcomes of this award though outreach activity, public engagement and using positive outcome to leverage further funding for the wider ophthalmic research community.

- Through outreach activities the group aims to stimulate interest and educate lay audiences about inherited disease, gene-directed therapies and personalised medicine and genetic disease. For example, the PI and her team will continue to partake in patient public involvement (PPI) events hosted by themselves and others, charitable fundraising events and outreach activities such as the 'Pint of Science' festival within the UK to inform and disseminate their research to varied and lay audiences.

- At a personal development level during this project an experimental postdoctoral researcher and an experienced bioinformatician will partake in specialist skills training and career development activities that will enhance their personal career trajectories.