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The University of Southampton
Medicine
Phone:
(023) 8120 8183
Email:
J.Ratnayaka@soton.ac.uk

Dr J. Arjuna Ratnayaka BSc, MPhil, DIC, PhD

Lecturer in Vision Sciences

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Dr J Arjuna Ratnayaka is a Lecturer in Vision Sciences (School of Medicine) at the University of Southampton.

Dr Ratnayaka brings together expertise in Retinal Cell Biology and Neurodegeneration. After graduating from the University of Aberdeen, Dr Ratnayaka completed a Master’s degree at Imperial College, London, followed by a PhD from the University of Liverpool. His doctoral work characterised the molecular/biochemical fate of proteins associated with Age-related Macular Degeneration (AMD) and proliferative vitreoretinopathy. He extended his interests in degenerative pathophysiology at King’s College London, and at the University of Sussex, where his postdoctoral work investigated axonal and synaptic mechanisms in the central nervous system. Dr Ratnayaka’s work helped unravel the molecular pathways of neurotransmission by describing how synaptic vesicles are shared by adjacent synapses, how signalling occurs via extra-synaptic sites and by uncovering novel mechanisms modulating synaptic plasticity.

His group at Southampton studies molecular mechanisms underlying degenerative pathophysiology in the senescent retina and brain. His team comprises of technical and postdoctoral staff as well as PhD students. Their work utilises in-vitro and animal models as well as human donor tissues, and employs techniques such as gene-editing, lentiviruses, stem cells, ultrastructural and 3D imaging. Dr Ratnayaka’s work involves collaborations with other scientists and clinicians as well as industrial partners. His portfolio includes supervision, teaching and mentoring across two Faculties, as well as acting as a PhD examiner. He is the Head of Field (Neuroscience, labs) for BMedSci projects and hosts MSc, MMedSc and BMedSci students in his laboratory.

Dr Ratnayaka is involved in raising awareness of blinding diseases as well as conditions such as Alzheimer’s and dementia through public lectures, workshops and outreach activities on behalf of charities. He also serves in several scientific and academic advisory panels, and acts as a peer-reviewer for grant-awarding bodies (UKRI and other UK/international research charities) as well as scientific journals in his area of expertise.

 

Qualifications

BSc (Hons) Biochemistry/Immunology, University of Aberdeen with a year industrial placement (Zeneca Pharmaceuticals), (1998)
MPhil (Medicine), DIC (Microbiology), Imperial College, London (2001)
PhD Metabolic and Cellular Medicine, University of Liverpool (2007)

 

Appointments held

Research Scientist, University of Manchester (2000-2001)

Research Assistant/Associate, University of Liverpool (2003-2006)

Postdoctoral Researcher, King’s College, London (2006-2009)

Research Fellow and Assistant Tutor, University of Sussex (2009-2013)

Lecturer in Vision Sciences, Faculty of Medicine, University of Southampton (2013-present

Research interests

Professional associations and membership

• Association for Research in Vision and Ophthalmology (ARVO)
• Anatomical Society
• Southampton Neuroscience Research Group (SoNG)
• Institute for Life Sciences (IfLS, University of Southampton)
• Interdisciplinary Dementia and Ageing Centre (IDaAC)

 

PhD Supervision

Charlotte L. Collier (co-supervisor) 2017- present

Chelsea Norman (co-supervisor) 2015 - 2019

Eloise E. Keeling (supervisor) 2015 - 2018

Savannah A. Lynn( supervisor) 2014 - 2017

Gareth Ward (co-supervisor) 2013 - 2016 

 

Degenerative changes in the ageing retina: The retina is affected by a variety of diseases that often results in irreversible sight loss. Examples include common conditions such as age-related macular degeneration (AMD) which is caused by genetic and lifestyle risk factors, as well as rare dystrophies including Sorsby Fundus Dystrophy (SFD) and Retinitis Pigmentosa. We use a combination of in-vitro and mouse models as well as donor human tissues to study how these retinopathies develop at cellular and tissue level. We use combinational approaches including techniques such as molecular cell biology, iPSCs, CRISPR/Cas9 and biochemistry, as well as ultrastructural and 2D/3D imaging. Our work aims to define retinal diseases in novel molecular terms, and help identify new targets for future treatments.

Recent highlights: We developed a mouse model of “dry” AMD as a tool for studying this irreversible form of blindness, and as a novel drug-discovery platform.

A lasered mouse model of retinal degeneration displays progressive outer retinal pathology providing insights into early geographic atrophy. Ibbett P et al. Sci Rep. 2019 May 16;9(1):7475.

We described and refined in-vitro cell models of the outer retina, which can be used to elucidate the degenerative pathophysiology of blinding diseases. We also established methods and protocols to study cargo trafficking and proteolytic mechanisms in retinal pigment epithelial (RPE) cells. 

A convenient protocol for establishing a human cell culture model of the outer retina. Lynn SA et al. F1000Res. 2018 Jul 18;7:1107. doi:10.12688/f1000research.15409.1.eCollection 2018.

Impaired Cargo Clearance in the Retinal Pigment Epithelium (RPE) Underlies Irreversible Blinding Diseases. Keeling E et al. Cells. 2018 Feb 23;7(2). pii: E16.

Ex-vivo models of the Retinal Pigment Epithelium (RPE) in long-term culture faithfully recapitulate key structural and physiological features of native RPE. Lynn SA et al. Tissue Cell. 2017 Aug;49(4):447-460.

 

Links between the degenerative retina and the brain: Degenerative conditions in the ageing retina and brain share remarkable similarities including defective trafficking, impaired autophagy, mitochondrial defects as well as the involvement of misfolding proteins such as Amyloid beta (Ab). Patients with neurological disorders such as Alzheimer’s and dementia also suffer from wide-ranging visual defects which are poorly understood. My work in this area investigates how retinal and brain pathologies could be linked, which include studies of shared biomarkers. My group is one of only a few UK laboratories studying diseases of the Retina-Brain axis. We combine molecular and proteomic assays with non-invasive approaches including funduscopy, fluorescein angiography, optical coherence tomography (OCT) and electroretinography (ERGs) to gain novel insights into the shared pathobiology of the senescent eye and brain. Our discoveries may help uncover new mechanisms underlying AD/dementia as well as complex retinopathies such as AMD.    

Recent highlights: Our studies have provided novel insights into how the Alzheimer’s-linked Ab proteins impair cells in the retina and associated tissues. 

The complexities underlying age-related macular degeneration: could amyloid beta play an important role? Lynn SA et al. Neural Regen Res. 2017 Apr;12(4):538-548.

Alzheimer’s-related amyloid beta peptide aggregates in the ageing retina: implications for sight loss and dementia. Ratnayaka, J. A & Lynn, S. (2016). In D. V. Moretti (Ed.), Update on Dementia (pp. 85-108). (Neuroscience). Rijeka, HR: INTECH. doi: 10.5772/64790

The Alzheimer's-related amyloid beta peptide is internalised by R28 neuroretinal cells and disrupts the microtubule associated protein 2 (MAP-2). Taylor-Walker G et al. Exp Eye Res. 2016 Dec;153:110-121.

 

Links between nutrition and retinal degeneration: Epidemiological and population studies show a strong link between the intake of unhealthy food (cholesterol and high fat-enriched foods referred to as a “Western-style” diet) and retinal damage. How disease pathways triggered by the intake of a poor diet results in pathology at cellular and tissue level is however, poorly understood. We use a combination of in-vitro and mouse models to identify the molecular pathways underpinning these changes. Our work aims to discover novel disease-causing mechanisms in the retina driven by diet alone; a powerful disease-linked risk factor that can be altered through choice of heathier foods and lifestyle.

Recent highlights: Our studies unravelled the molecular pathways linked with retinal damage in individuals consuming an unhealthy “Western-style” diet. This was one of the most widely read articles of 2018-19 in the journal.

Oxidative Stress and Dysfunctional Intracellular Traffic Linked to an Unhealthy Diet Results in Impaired Cargo Transport in the Retinal Pigment Epithelium (RPE). Keeling E et al. Mol Nutr Food Res. 2019 Aug;63(15):e1800951.

 

Links between genetics underpinning ocular diseases and cellular changes: Although genetic mutations associated with many ocular pathologies have been identified, how these translate to molecular changes in retinal cells/tissues are less clear. In collaborative studies with geneticists, my work in this area aims to identify novel links between genetics and cellular pathology, so effective screening and treatments can be developed for conditions such as albinism and nystagmus. 

A small gene sequencing panel realises a high diagnostic rate in patients with congenital nystagmus following basic phenotyping. O'Gorman L et al. Sci Rep. 2019 Sep 13;9(1):13229.

Identification of a functionally significant tri-allelic genotype in the Tyrosinase gene (TYR) causing hypomorphic oculocutaneous albinism (OCA1B). Norman CS et al. Sci Rep. 2017 Jun 30;7(1):4415.

Research Opportunities
Enquiries are welcome from scientists and clinicians as well as potential industrial partners to work on existing or new projects utilizing the expertise developed in my group. Interlinking research themes spanning diseases of the eye and brain helps study ocular and brain disorders from a novel and cohesive perspective. Enquiries are also welcome from prospective postdoctoral scientists including Marie Curie Fellows. Queries from independently funded non-UK/EU students interested in undertaking work leading to a PhD are welcome. Undergraduate and postgraduate students from the University of Southampton interested in short-term projects are encouraged to contact me in the first instance.

 

ORCID ID https://orcid.org/0000-0002-1027-6938

In-vitro modeling and scaffolds crop
Figure 1
Trafficking studies
Figure 2
3D Studies
Figure 3
Mouse Studies
Figure 4
Fibre Optic nerve
Figure 5

Department(s)

Clinical and Experimental Sciences

Affiliate Department(s)

Institute for Life Sciences, Southampton Neuroscience Group (SoNG) , Biomedical Imaging Unit, Gift of Sight Appeal, Alzheimer’s Research UK South Coast Network

Undergraduate and postgraduate supervision

Principal supervisor for the following students

2020: Usaid Yousaf, BMedSci student

2019: Annabelle Culling, MMedSc student

2019: Daisy Badcock, MSc student

2019: Kyle English, BMedSci student

2018: Ben Jenkins, MMedSc student

2018: Esther Thomas, BMedSci student

2018: Thibana Thisainathan, Summer internship

2018: Dillon Davis, Summer internship, Wilkes University, PA, USA

2017: Ruaridh Weaterton, MMedSc student

2017: Yen M. Koh, MSc student

2017: Rhys Richards, BMedSci student

2017: Dillon Davis, Summer internship, Wilkes University, PA, USA (Dr Joseph Donald Stephens, DDS Global Scholars Program)

2016: Nicole Y.T. Tan, MMedSc student

2016: Alexander Simpson, MSc student

2016: Joanne Richards, MSc student

2016: Roshni Desai, BMedSci student

2015: Eloise Keeling, PhD student

2015: George Taylor-Walker, MSc student

2015: Cristina Musat, BMedSci student

2015: Louise Taylor, BMedSci student

2015: Rosie Munday, BSc student

2015: Annalize Brooks, BSc student

2015: Louis Taylor, BMedSci student

2014: Savannah Lynn, PhD student

2014: Tommy Freeman, MSc student

2014: Aaron Kendall, BMedSci student

2014: Gagandeep Gabha, BSc student

 

Co-supervisor for the following students

2017: Charlotte L. Collier, PhD student

2015: Chelsea Norman, PhD student

2015: Vincent Morese, MSc student

2014: Gareth Ward, PhD student

 

National and International responsibilities

2020: Academic advisor to the Commonwealth Scholarship Commission

2018: Grant assessment panel, National Centre for the Replacement Refinement & Reduction of Animals in Research (NC3Rs)

2018: Collaboration/consultant to SMEs and Pharma

2017: Manager, Southampton Eye Biobank

2017: Scientific advisory board, National Eye Research Centre (NERC)

2016: Panel member, CRACK-IT Challenge, NC3Rs

2015: Committee member, Alzheimer’s Research UK South Coast Network

2015: Board member, Gift of Sight Appeal

2015: Steering committee, Southampton Neuroscience Group (SoNG)

2014: Fight for Sight, Speaker Network

2014: Peer-reviewer UKRI and the Wellcome Trust as well as other UK/international grant awarding bodies

2014: Peer-reviewer for scientific journals in my area of expertise

2013: Senior research team and scientific advisory board, Gift of Sight Appeal

2013: Speaker for eye and dementia charities and patient support groups

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Articles

Book Chapters

Conferences

BM5 programme (Faculty of Medicine)

BIOL 6078: (Biological Sciences, Faculty of Natural & Environmental Sciences)

BIOL3034: Research projects (Biological Sciences, Faculty of Natural & Environmental Sciences)

BIOL6013: In depth research projects (Biological Sciences, Faculty of Natural & Environmental Sciences)

BMedSci programme: Head of Field (Neuroscience laboratory projects), Faculty of Medicine

BMedSci: Project supervision (Faculty of Medicine) 

MMedSc: Project supervision (Faculty of Medicine)

Personal academic tutor (Faculty of Medicine)

Wessex Regional Postgraduate (Ophthalmology) teaching, Faculty of Medicine

Biomedical Imaging Unit (BIU): light and confocal microscopy teaching

 

External Teaching

“Meet the Scientist” teaching, Lifelab, University of Southampton

Dr Ratnayaka is involved in numerous public engagement and outreach activities, which are carried out on behalf of academic as well as research organisations funded by the government and the charities sector.

Speaker (ocular nutrition) Macular Society Conference, London 2019
Speaker (ocular nutrition) Macular Society Conference, London 2019
Irish College of Ophthalmology Conference, Galway 2019
Irish College of Ophthalmology Conference, Galway 2019
Brain and Ocular Nutrition Conference
Brain and Ocular Nutrition Conference
Dr J. Arjuna Ratnayaka
Tel: +44 (0)23 8120 8183 Email: J.Ratnayaka@soton.ac.uk
University of Southampton.
CES, Faculty of Medicine,
South Academic and Path Block, MP 806, SGH, Tremona Road,
Southampton SO16 6YD,
United Kingdom.

Room Number: SGH/South Academic and Path Block/MP808

Telephone:(023) 8120 8183
Email:J.Ratnayaka@soton.ac.uk

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