The Epigenetic Contribution to Keratoconus

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dc.contributor.advisor Oliver, V en
dc.contributor.advisor Sherwin, T en Mukhtar, Anthony en 2018-06-05T21:16:48Z en 2018 en
dc.identifier.uri en
dc.description Full text is available to authenticated members of The University of Auckland only. en
dc.description.abstract Keratoconus is a progressive corneal disease which causes the cornea to weaken and become conical in morphology, severely impacting vision and quality of life. Environmental factors and genetic factors have been known to contribute to the progression of keratoconus especially, within New Zealand’s Māori and Pacific populations. Previous studies have suggested that keratoconus is linked to the inflammation, oxidative stress and epithelial-to-mesenchymal pathways. We hypothesised that epigenetics, the interplay of environmental and genetic factors, contributes to keratoconus. We used immunohistochemistry to characterise different protein expression within normal corneas and keratoconic corneas sections. Then we treated cultured corneal epithelial cells with the DNA methylation altering drug 5-azacytidine to recreate the expression pattern seen in keratoconic tissue. We had also used rt-qPCR and ddPCR to investigate whether our 5-azacytidine treated corneal epithelial cell cultures would differentially express genes which have previously been associated with keratoconus. We found that keratoconus tissue sections had increased mesenchymal biomarkers such as vimentin and a decrease in epithelial biomarkers such as tight junction protein 1 within the epithelium. Additionally, within our histology sections we observed epithelial cells which appeared to be transitioning through the basal epithelium into the stroma expressing these proteins. This may contribute to the loss of structural integrity and cellular attrition in the clinical manifestation of keratoconus. Cytoplasmic SOD1 and various cytokines (TNF and MMP9) were also irregularly expressed within keratoconic tissue and regularly expressed within normal corneal tissue, which suggests keratoconic tissue has a predisposition towards build-up of reactive oxygen species. Although we were not able to show that our 5-azacytidine treatment affected gene expression at a statistically significant level, trends in our data suggest that there still may be an observable effect. Overall, we showed that the epithelium-to-mesenchymal transition is likely being induced in keratoconic tissue, and increased oxidative stress and inflammation may be a driving mechanism for this change. Our exploration into the change of DNA methylation in our methylation-sensitive quantitative PCR-based assay, although unsuccessful our cell culture experiments suggested that epigenetic mechanisms play a role in keratoconus. Although this pilot study does not prove an epigenetic-link, it suggests and provides evidence for an epigenetic contribution for future studies to expand upon. en
dc.publisher ResearchSpace@Auckland en
dc.relation.ispartof Masters Thesis - University of Auckland en
dc.relation.isreferencedby UoA99265066312702091 en
dc.rights Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher. en
dc.rights Restricted Item. Available to authenticated members of The University of Auckland. en
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dc.rights.uri en
dc.title The Epigenetic Contribution to Keratoconus en
dc.type Thesis en Biomedical Science en The University of Auckland en Masters en
dc.rights.holder Copyright: The author en
pubs.elements-id 743831 en
pubs.record-created-at-source-date 2018-06-06 en

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