About the Project
Background: Age-related macular degeneration (AMD) is the leading cause of impaired vision and blindness in over 50s for which treatments are limited to a small subset of sufferers. Central to AMD onset and progression are the malfunction and degeneration of the retinal pigment epithelium (RPE) – a non-regenerative, cellular monolayer essential for photoreceptor function. RPE functions become disrupted with age and are associated with pathological events, in and around the retina, due to life-long oxidative damage from daily phagocytosis of photoreceptors and intense metabolism. While ageing increases significantly the risk of developing AMD, there are also numerous genetic risk factors at play. One of these is the genetic variant B of the potent cysteine proteinase inhibitor cystatin C. One of the top 1% expressed and secreted RPE proteins and a key proteolysis regulator, cystatin C appears to be central to various mechanisms related to neurodegenerative processes, both in AMD and Alzheimer’s disease, including mitochondrial dysfunction and protein aggregation. Unveiling how these changes occur and how they lead to disease is essential to exploiting this knowledge for developing new therapeutic strategies for these major diseases.
Work on which the PhD project builds: In RPE cells we know that, compared with wild-type cystatin C, the disease-associated variant B has compromised intracellular trafficking, reduced secretion and unexpected mitochondrial association. Furthermore, cystatin C shows a significant age-related reduction in the human central retina (macula) in situ. Exciting recent comparative analysis of interacting proteins of wild-type and variant B cystatin C in RPE cells identified several outer mitochondrial membrane proteins that exclusively bound to the variant. We developed recently a “AMD-in-a-dish” cell model through an innovative application of CRISPR/Cas9 gene editing. Further preliminary functional data in CRISPR/Cas9-gene edited induced pluripotent stem cells (iPSCs)-derived and differentiated RPE cells indicate increased mitochondrial membrane potential and reactive oxygen species production.
PhD project objective: To model and characterise the molecular mechanisms of variant B cystatin C-induced pathological changes of RPE dysfunction leading to AMD development.
Experimental approach: The interdisciplinary approach combines use of advanced in vitro experimental models (gene edited iPSCs-derived and differentiated RPE cells, long-term, age-stressed cultures), functional molecular/cellular assays, bioinformatics modelling and cell imaging.
Training: The student will be offered multidisciplinary training combining molecular/cell biology and microscopy with highly topical skills in data science/computational modelling and systems biology. While primarily based in the Ocular Molecular Biology and Mechanisms of Disease Group in Liverpool (http://www.liv.ac.uk/paraoan) which is focused on understanding the regulation of RPE functions in health, ageing and retinal degeneration, the student will benefit from the collaboration with the integrative bioinformatics and computational modelling group in Newcastle, developing skills that will be vital for future Biosciences research. An initial rotation (up to 3 months, dependent on the student’s background) in the Newcastle Biosciences Institute to develop these skills will take place during the first year. The student will have the opportunity to attend vision and systems biology conferences benefitting from the groups’ multiple international collaborations.
Informal enquiries are welcome and should be made at: [Email Address Removed]
Benefits of being in the DiMeN DTP:
This project is part of the Discovery Medicine North Doctoral Training Partnership (DiMeN DTP), a diverse community of PhD students across the North of England researching the major health problems facing the world today. Our partner institutions (Universities of Leeds, Liverpool, Newcastle and Sheffield) are internationally recognised as centres of research excellence and can offer you access to state-of the-art facilities to deliver high impact research.
We are very proud of our student-centred ethos and committed to supporting you throughout your PhD. As part of the DTP, we offer bespoke training in key skills sought after in early career researchers, as well as opportunities to broaden your career horizons in a range of non-academic sectors.
Being funded by the MRC means you can access additional funding for research placements, international training opportunities or internships in science policy, science communication and beyond. See how our current DiMeN students have benefited from this funding here: http://www.dimen.org.uk/overview/student-profiles/flexible-supplement-awards
Further information on the programme and how to apply can be found on our website:
Studentships commence: 1st October 2021
Supharattanasitthi W, Sharif U, Carlsson E, Paraoan L. (2019) CRISPR/Cas9-mediated one step bi-allelic change of genomic DNA in iPSCs and human RPE cells in vitro with dual antibiotic selection. Sci Rep. 9(1):174.
Paraoan L*, Hiscott P, Gosden C, Grierson I. (2010) Cystatin C in macular and neuronal degenerations: Implications for mechanism(s) of Age-related Macular Degeneration. Vision Res. 50(7):737-742
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