Biology subjects

Goodbourn, P. T.

Publications and source records attributed to Goodbourn, P. T..

3 recordsLinked to original sources

bioRxiv2023

EFEMP1 contributes to light-dependent ocular growth in zebrafish

Myopia (short-sightedness) is the most common ocular disorder. It generally develops after over-exposure to aberrant visual environments, disrupting emmetropization mechanisms that should match eye growth with optical power. A pre-screening of strongly associated myopia-risk genes identified through human genome-wide association studies implicates efemp1 in myopia development, but how this gene impacts ocular growth remains unclear. Here, we modify efemp1 expression specifically in the retina of zebrafish. We found that under normal lighting, efemp1 mutants developed axial myopia, enlarged eyes, reduced spatial vision and altered retinal function. However, under myopia-inducing dark-rearing, compared to control fish, mutants remained emmetropic and showed changes in retinal function. Efemp1 modification changed the expression of efemp1, egr1, tgfb1a, vegfab and rbp3 genes in the eye, and changes the inner retinal distributions of myopia-associated EFEMP1, TIMP2 and MMP2 proteins. Efemp1 modification also impacted dark-rearing-induced responses of vegfab and wnt2b genes and above-mentioned myopia-associated proteins. Together, we provided robust evidence that light-dependent ocular growth is regulated by efemp1. SummaryThis study shows that retina-specific modification of efemp1 expression in zebrafish results in myopic eye, and impacts responses to myopia-inducing dark-rearing in eye growth, retinal function, and myopia-associated molecular expression and distribution, implicating light-dependent regulation of efemp1 in ocular development.

neuroscience↗

bioRxiv2023

Establishment and comprehensive characterization of a novel dark-reared zebrafish model for myopia studies

PurposeMyopia is predicted to impact approximately 5 billion people by 2050, necessitating mechanistic understanding of its development. Myopia results from dysregulated genetic mechanisms of emmetropization, caused by over-exposure to aberrant visual environments; however, these genetic mechanisms remain unclear. Recent human genome-wide association studies have identified a range of novel myopia-risk genes. To facilitate large-scale in vivo mechanistic examination of gene-environment interactions, this study aims to establish a myopia model platform that allows efficient environmental and genetic manipulations. MethodsWe established an environmental zebrafish myopia model by dark-rearing. Ocular biometrics including relative ocular refraction were quantified using optical coherence tomography images. Spatial vision was assessed using optomotor response (OMR). Retinal function was analyzed via electroretinography (ERG). Myopia-associated molecular contents or distributions were examined using RT-qPCR or immunohistochemistry. ResultsOur model produces robust phenotypic changes, showing myopia after 2 weeks of dark-rearing, which were recoverable within 2 weeks after returning animals to normal lighting. 2-week dark-reared zebrafish have reduced spatial-frequency tuning function. ERG showed reduced photoreceptor and bipolar cell function (a- and b-waves) after only 2 days of dark-rearing, which worsened after 2 weeks of dark-rearing. We also found dark-rearing-induced changes to expression of myopia-risk genes, including egr1, vegfaa, vegfab, rbp3, gjd2a and gjd2b, inner retinal distribution of EFEMP1, TIMP2 and MMP2, as well as transiently reduced PSD95 density in the inner plexiform layer. ConclusionsCoupled with the gene editing tools available for zebrafish, our environmental myopia model provides an excellent platform for large-scale investigation of gene-environment interactions in myopia development.

neuroscience↗

bioRxiv2020

Altered visual function in a larval zebrafish knockout of neurodevelopmental risk gene pdzk1

The human PDZK1 gene is located in a genomic susceptibility region for neurodevelopmental disorders. A genome-wide association study (GWAS) identified links between PDZK1 polymorphisms and altered visual contrast sensitivity, an endophenotype for schizophrenia and autism spectrum disorder. The PDZK1 protein is implicated in neurological functioning, interacting with synaptic molecules including post-synaptic density 95 (PSD-95), N-methyl-D-aspartate receptors (NMDAR), corticotropin-releasing factor receptor 1 (CRFR1) and serotonin 2A receptors. To elucidate the role of PDZK1, we generated pdzk1-knockout (pdzk1-KO) zebrafish using CRISPR/Cas-9 genome editing. Visual function of 7-day-old fish was assessed at behavioural and functional levels using the optomotor response (OMR) and scotopic electroretinogram (ERG). We also quantified retinal morphology and densities of PSD-95, NMDAR1, CRFR1 and serotonin in the synaptic inner plexiform layer at 7 days, 4 weeks and 8 weeks of age. Relative to wild-type, pdzk1-KO larvae showed spatial-frequency tuning functions with increased amplitude (likely due to abnormal gain control) and reduced ERG b-waves (suggestive of inner retinal dysfunction). However, these functional differences were not associated with gross synaptic or morphological retinal phenotypes. The findings corroborate a role for pdzk1 in visual function, and our model system provides a platform for investigating other genes associated with abnormal visual behaviour.

neuroscience↗