Project description:Ocular growth is regulated locally by signals produced in the retina that ultimately act on the growth of the scleral tissue. Consequently, a number of studies have investigated changes in retinal gene expression during manipulation of ocular growth in an attempt to elucidate the biochemical pathways underlying eye growth. However, due to the highly heterogenous nature of the retina, important changes in gene expression can be masked. Therefore, this study has investigated changes in gene expression specifically within the retinal amacrine cell layer, the most likely generator of growth signals, during manipulations of ocular growth. Chicks were monocularly treated with either -7D (n=3, growth stimulant) or +7D (n=3, growth suppressant) lenses for 24hrs, with untreated age-matched chicks serving as a control (n=3). Total RNA from the amacrine cell layer was isolated from laser-capture microdissected (Zeiss, Bernried, Germany) 10µm thick sections. Labeled cRNA was prepared from three separate samples per condition and hybridized to Affymetrix GeneChip Chicken Genome arrays.
Project description:Refractive eye development is regulated by optical defocus in a process of emmetropization. Excessive exposure to negative optical defocus often leads to the development of myopia. However, it is still largely unknown how optical defocus is detected by the retina. Here, we used genome-wide RNA-sequencing (RNA-seq) to conduct analysis of the retinal genetic networks underlying contrast perception and refractive eye development. We report that the genetic network subserving contrast perception plays an important role in optical defocus detection and emmetropization. Our results demonstrate an interaction between contrast perception, the retinal circadian clock pathway and the signaling pathway underlying optical defocus detection. We also observe that the relative majority of genes causing human myopia are involved in the processing of optical defocus. Together, our results support the hypothesis that optical defocus is perceived by the retina using contrast as a proxy and provide new insights into molecular signaling underlying refractive eye development.
Project description:In chicks, the avian homologue of the early growth response protein-1 (ZENK) has been shown to be increased in a special cell type of the retina, the glucagonergic amacrine cells, under conditions that lead to a reduction in eye growth (myopic defocus, recovery of myopia) and decreased under conditions that enhance ocular growth (hyperopic defocus, form-deprivation). The investigation of Egr-1 knock-out mice showed that homozygous knock-out mice with no functional Egr-1 protein developed relative axial myopia at the age of 42 and 56 days, compared to heterozygous- and wildtype Egr-1 knock-out mice. To clarify the role of Egr-1 in the retinal regulation of eye growth, and to get an idea about the biochemical pathways underlying this mechanism, we studied the role of Egr-1 in more detail using Affymetrix microarrays. Experiment Overall Design: Retinal samples of young homozygous Egr-1 knock-out and wildtype mice at the age of 30 days (hm30 and wt30; no difference in axial eye length yet) and 42 days (hm42 and wt42; already a difference in axial eye length of 59 µm) were taken to compare the mRNA expression changes over time between these two genotypes and within the same genotype between the two age groups.
Project description:In chicks, the avian homologue of the early growth response protein-1 (ZENK) has been shown to be increased in a special cell type of the retina, the glucagonergic amacrine cells, under conditions that lead to a reduction in eye growth (myopic defocus, recovery of myopia) and decreased under conditions that enhance ocular growth (hyperopic defocus, form-deprivation). The investigation of Egr-1 knock-out mice showed that homozygous knock-out mice with no functional Egr-1 protein developed relative axial myopia at the age of 42 and 56 days, compared to heterozygous- and wildtype Egr-1 knock-out mice. To clarify the role of Egr-1 in the retinal regulation of eye growth, and to get an idea about the biochemical pathways underlying this mechanism, we studied the role of Egr-1 in more detail using Affymetrix microarrays.
Project description:Newly-hatched domestic chick serves as an important model for studies of neural and behavioral plasticity, particularly with respect to learning and memory such as filial imprinting. Imprinting is assumed to be a unique case of recognition learning with some characteristic features, such as sensitive period and irreversibility. However, the molecules involved in the memory process are yet to be fully identified. To address this issue, we attempted to identify the genes differentially expressed at an earlier phase of filial imprinting than described in our previous report (Brain Res. Bull.76, 275-281 (2008)). One-day-old chicks were trained for imprinting for 1 h and whole brains were collected and used for cDNA microarray analysis and quantitative RT-PCR. We identified 18 genes upregulated accompanying filial imprinting. These results suggested that the increase of these 18 genes associated with filial imprinting might play an important role in the acquisition of memory in the filial imprinting. Total RNA was extracted from whole brains of trained chicks (n=16) and control dark-reared chicks (n=16). Using these total RNAs, we performed RT-PCR to distinguish male chicks from females. Then total RNAs were separated and mixed in four groups (1, male trained (n=8); 2, female trained (n=8); 3, male dark-reared (n=8); and 4, female dark-reared chicks (n=8)), and we performed cDNA microarray expression analysis to identify the upregulated genes following imprinting (1 versus 3 and 2 versus 4).
Project description:We sequenced mRNA from 34 retina/RPE/choroid samples taken from the right eyes of male chicks across a time-course of normal development or refractive error induction (defocus-induced myopia and hyperopia).
Project description:The retina plays an important regulatory role in ocular growth. To screen for new retinal candidate genes that could be involved in the inhibition of ocular growth, we used chick microarrays to analyze the changes in retinal mRNA expression after myopic defocus was imposed by positive lens-wear. Chicks were raised under a 12h-light/12h-dark cycle (light-onset: 8:00 am and light-offset: 8:00 pm) with unrestricted access to water and food. On the day prior to the experiment, velcro rings were glued to the feathers around the eye under diethylether anaesthesia. Four male white leghorn chicks, aged 9 days, wore +6.9D spectacle lenses over both eyes for 24 hours. Four untreated age-matched male chicks from the same batch served as controls. After decapitation of the chicks, the eyes were enucleated and the retina was prepared. The retinae from both eyes of each chick were pooled for RNA isolation. Experiment Overall Design: Four samples each: Retina of both eyes of +6.9 diopter lens-treated chicks (plus_lens), Retina of both eyes of untreated control chicks (control)
Project description:The retina plays an important regulatory role in ocular growth. To screen for new retinal candidate genes that could be involved in the inhibition of ocular growth, we used chick microarrays to analyze the changes in retinal mRNA expression after myopic defocus was imposed by positive lens-wear. Chicks were raised under a 12h-light/12h-dark cycle (light-onset: 8:00 am and light-offset: 8:00 pm) with unrestricted access to water and food. On the day prior to the experiment, velcro rings were glued to the feathers around the eye under diethylether anaesthesia. Four male white leghorn chicks, aged 9 days, wore +6.9D spectacle lenses over both eyes for 24 hours. Four untreated age-matched male chicks from the same batch served as controls. After decapitation of the chicks, the eyes were enucleated and the retina was prepared. The retinae from both eyes of each chick were pooled for RNA isolation. Keywords: gene expression comparison