Centre for Eye Research Australia (CERA) - Research Publications
Now showing items 1-12 of 166
Multi-species single-cell transcriptomic analysis of ocular compartment regulons
(NATURE PORTFOLIO, 2021-09-28)
The retina is a widely profiled tissue in multiple species by single-cell RNA sequencing studies. However, integrative research of the retina across species is lacking. Here, we construct the first single-cell atlas of the human and porcine ocular compartments and study inter-species differences in the retina. In addition to that, we identify putative adult stem cells present in the iris tissue. We also create a disease map of genes involved in eye disorders across compartments of the eye. Furthermore, we probe the regulons of different cell populations, which include transcription factors and receptor-ligand interactions and reveal unique directional signalling between ocular cell types. In addition, we study conservation of regulons across vertebrates and zebrafish to identify common core factors. Here, we show perturbation of KLF7 gene expression during retinal ganglion cells differentiation and conclude that it plays a significant role in the maturation of retinal ganglion cells.
Prevalence, associations and characteristics of severe uncorrected refractive error in the Australian National Eye Health Survey
IMPORTANCE: In Australia, nationally representative data of the burden and associations of severe uncorrected refractive error are scarce. BACKGROUND: To report the prevalence and characteristics of severe uncorrected refractive error in Indigenous and non-Indigenous Australians. DESIGN: Population-based cross-sectional study. PARTICIPANTS: A total of 3098 non-Indigenous Australians aged 50 to 98 and 1738 Indigenous Australians aged 40 to 92 living in 30 randomly selected Australian sites were examined. METHODS: Severe uncorrected refractive error was defined as an improvement of ≥2 lines on the logMAR chart in one or both eyes in participants with a presenting visual acuity <6/12. MAIN OUTCOME MEASURE: Severe uncorrected refractive error RESULTS: Prevalence of severe uncorrected refractive error was 11.0% (95% confidence interval 9.3-13.0) in non-Indigenous and 14.5% (12.5-16.7) in Indigenous Australians. Eighty-two percent of non-Indigenous and 77% of Indigenous participants had a spherical equivalent refraction between -2.00D and +2.00D. Indigenous Australians who were older (odds ratio [OR] for 70-79 years vs 40-49 years = 3.59), resided in outer regional areas (OR = 1.78) and did not have an eye examination in the previous 2-years (OR = 1.50) were associated with higher odds of severe uncorrected refractive error. Geographical remoteness (OR = .68 for inner regional), male gender (OR = 1.30), older age (OR for 70-79 years vs 50-59 years = 1.51) and failure to have an eye examination in the previous 2-years (OR = 2.06) were associated with severe uncorrected refractive error among non-Indigenous participants. CONCLUSIONS AND RELEVANCE: Increased public awareness of the importance of regular optometric examinations may be required in groups at high risk of severe uncorrected refractive error.
Impact of type 2 diabetes on hospitalization and mortality in people with malignancy
AIM: To compare the characteristics of and outcomes for people with malignancies with and without a co-diagnosis of diabetes. METHODS: Emergency department and hospital discharge data from a single centre for the period between 1 January 2015 and 31 December 2017 were used to identify people with a diagnosis of a malignancy and diabetes. Multivariate Cox regression models were used to estimate the effect of diabetes on all-cause mortality. A truncated negative binomial regression model was used to assess the impact of diabetes on length of hospital inpatient stay. Prentice-Williams-Peterson total time models were used to assess the effect of diabetes on number of emergency department re-presentations and inpatient re-admissions. RESULTS: Of 7004 people identified with malignancies, 1195 (17.1%) were also diagnosed with diabetes. A diagnosis of diabetes was associated with a greater number of inpatient re-admissions [adjusted hazard ratio 1.13 (95% CI 1.03, 1.24)], a greater number of emergency department re-presentations [adjusted hazard ratio 1.13 (95% CI 1.05, 1.22)] and longer length of stay [adjusted incidence rate ratio 1.14 (95% CI 1.04, 1.25)]. A co-diagnosis of diabetes was also associated with a 48% increased risk of all-cause mortality [adjusted hazard ratio 1.48 (95% CI 1.22-1.76)]. CONCLUSIONS: People with malignancies and diabetes had significantly more emergency department presentations, more inpatient admissions, longer length of hospital stay and higher rates of all-cause mortality compared to people with a malignancy without diabetes.
A single-cell transcriptome atlas of the adult human retina
The retina is a specialized neural tissue that senses light and initiates image processing. Although the functional organization of specific retina cells has been well studied, the molecular profile of many cell types remains unclear in humans. To comprehensively profile the human retina, we performed single-cell RNA sequencing on 20,009 cells from three donors and compiled a reference transcriptome atlas. Using unsupervised clustering analysis, we identified 18 transcriptionally distinct cell populations representing all known neural retinal cells: rod photoreceptors, cone photoreceptors, Müller glia, bipolar cells, amacrine cells, retinal ganglion cells, horizontal cells, astrocytes, and microglia. Our data captured molecular profiles for healthy and putative early degenerating rod photoreceptors, and revealed the loss of MALAT1 expression with longer post-mortem time, which potentially suggested a novel role of MALAT1 in rod photoreceptor degeneration. We have demonstrated the use of this retina transcriptome atlas to benchmark pluripotent stem cell-derived cone photoreceptors and an adult Müller glia cell line. This work provides an important reference with unprecedented insights into the transcriptional landscape of human retinal cells, which is fundamental to understanding retinal biology and disease.
Amyloid precursor protein-mediated mitochondrial regulation and Alzheimer's disease
Despite clear evidence of a neuroprotective physiological role of amyloid precursor protein (APP) and its non-amyloidogenic processing products, APP has been investigated mainly in animal and cellular models of amyloid pathology in the context of Alzheimer's disease. The rare familial mutations in APP and presenilin-1/2, which sometimes drive increased amyloid β (Aβ) production, may have unduly influenced Alzheimer's disease research. APP and its cleavage products play important roles in cellular and mitochondrial metabolism, but many studies focus solely on Aβ. Mitochondrial bioenergetic metabolism is essential for neuronal function, maintenance and survival, and multiple reports indicate mitochondrial abnormalities in patients with Alzheimer's disease. In this review, we focus on mitochondrial abnormalities reported in sporadic Alzheimer's disease patients and the role of full-length APP and its non-amyloidogenic fragments, particularly soluble APPα, on mitochondrial bioenergetic metabolism. We do not review the plethora of animal and in vitro studies using mutant APP/presenilin constructs or experiments using exogenous Aβ. In doing so, we aim to invigorate research and discussion around non-amyloidogenic APP processing products and the mechanisms linking mitochondria and complex neurodegenerative disorders such as sporadic Alzheimer's disease. LINKED ARTICLES: This article is part of a themed section on Therapeutics for Dementia and Alzheimer's Disease: New Directions for Precision Medicine. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.18/issuetoc.
Current state and future prospects of artificial intelligence in ophthalmology: a review
Artificial intelligence (AI) has emerged as a major frontier in computer science research. Although AI has broad application across many medical fields, it will have particular utility in ophthalmology and will dramatically change the diagnostic and treatment pathways for many eye conditions such as corneal ectasias, glaucoma, age-related macular degeneration and diabetic retinopathy. However, given that AI has primarily been driven as a computer science, its concepts and terminology are unfamiliar to many medical professionals. Important key terms such as machine learning and deep learning are often misunderstood and incorrectly used interchangeably. This article presents an overview of AI and new developments relevant to ophthalmology.
Relationship between reticular pseudodrusen and choroidal thickness in intermediate age-related macular degeneration
IMPORTANCE: Reticular pseudodrusen (RPD) is strongly associated with late age-related macular degeneration (AMD) but their aetiology remains unknown. RPD have been associated with reduced choroidal thickness (ChT) but most studies are limited by small sample size and varying severity of AMD. BACKGROUND: To investigate the relationship between choroidal thickness and RPD in eyes with intermediate AMD (iAMD), controlling for variables known to influence ChT. DESIGN: Retrospective cohort study. PARTICIPANTS: Participants were recruited from Centre for Eye Research Australia. METHODS: Colour fundus photographs, fundus auto fluorescence, near-infrared and spectral-domain ocular coherence tomography (OCT) were graded for RPD. ChT was measured from enhanced-depth imaging OCT scans at the centre of fovea, 1500 and 3000 μm nasal, temporal, superior and inferior from centre of fovea. MAIN OUTCOME MEASURES: ChT between RPD and non-RPD group. RESULTS: A total of 297 eyes from 152 subjects were included. A total of 84 (28%) had RPD and were older than non-RPD group (75.1 ± 5.4 years and 68.7 ± 6.9 years, respectively; P < 0.001). In unadjusted analysis, the RPD group was significantly associated with thinner choroids across all measured locations (P ≤ 0.022). After adjustment for variables, the presence of RPD was no longer associated with ChT (P ≥ 0.132 for all locations) but age (P < 0.001) and refractive error (P = 0.002) remained significantly associated with ChT. CONCLUSIONS AND RELEVANCE: Age and refractive error, rather than RPD, was significantly associated with reduced ChT in eyes with iAMD. Choroidal insufficiency may be a less important variable in RPD aetiology than previously considered.
Lipid-lowering therapy use and achievement of cholesterol targets in an Australian diabetes clinic
We documented temporal changes in the use of lipid-lowering medications and achievement of cholesterol targets in an Australian diabetes clinic. The number of patients using lipid-lowering therapy for primary or secondary cardiovascular prevention increased from 6 to 69% between 1993-1995 and 2014-2016, which corresponded to a decrease in low-density lipoprotein cholesterol levels from 3.7 to 2.4 mmol/L (P < 0.01).
miRNA involvement in angiogenesis in age-related macular degeneration
Age-related macular degeneration (AMD) is the leading cause of blindness in the elderly. Late-stage AMD is characterized by choroidal neovascularization (CNV). miR-93 appears to play a role in regulating vascular endothelial growth factor-A (VEGF-A), a known factor involved in neovascularization. Understanding its biological significance might enable development of therapeutic interventions for diseases like AMD. We aimed to determine the role of miR-93 in AMD using a laser-induced CNV mouse model. CNV was induced by laser photocoagulation in C57BL/6 mice. The CNV mice were transfected with scrambled miR or miR-93 mimic. The treatment effect was assessed by fundus photography and fluorescein angiography and confirmed by choroidal flatmount. The expression of miR-93 and VEGF-A in ocular tissues was analysed by quantitative polymerase chain reaction (qPCR) and Western blot. The overexpression effects of miR-93 were also proved on human microvascular endothelial cells (HMECs). Significantly decreased expression of miR-93 was observed by qPCR analysis in CNV mice compared to untreated mice (p < 0.05). VEGF-A messenger RNA (mRNA) and protein expression were upregulated with CNV; these changes were ameliorated by restoration of miR-93 (p < 0.05). CNV was reduced after miR-93 transfection. Transfection of miR-93 reduced the proliferation of HMECs (p < 0.01), but no significant changes were observed in 2D capillary-like tube formation (p > 0.05) and migration (p > 0.05) compared with that in the untreated cells. miR-93 has been shown to be a negative modulator of angiogenesis in the eye. All together, these results highlight the therapeutic potential of miR-93 and suggest that it may contribute as a putative therapeutic target for AMD in humans.
Human Mitoribosome Biogenesis and Its Emerging Links to Disease
Mammalian mitochondrial ribosomes (mitoribosomes) synthesize a small subset of proteins, which are essential components of the oxidative phosphorylation machinery. Therefore, their function is of fundamental importance to cellular metabolism. The assembly of mitoribosomes is a complex process that progresses through numerous maturation and protein-binding events coordinated by the actions of several assembly factors. Dysregulation of mitoribosome production is increasingly recognized as a contributor to metabolic and neurodegenerative diseases. In recent years, mutations in multiple components of the mitoribosome assembly machinery have been associated with a range of human pathologies, highlighting their importance to cell function and health. Here, we provide a review of our current understanding of mitoribosome biogenesis, highlighting the key factors involved in this process and the growing number of mutations in genes encoding mitoribosomal RNAs, proteins, and assembly factors that lead to human disease.