Genome-wide analysis of retinal transcriptome reveals common genetic network underlying perception of contrast and optical defocus detection
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ABSTRACT: 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:During postnatal development, the optical geometry of the eye is refined through a process called emmetropization. During eye emmetropization, optical defocus triggers a signaling cascade that originates in the retina, propagates across other ocular tissues and results in scleral wall remodeling. This signaling is associated with large-scale changes in gene expression, which was extensively studied at the mRNA level. Although several studies investigated the role of non-coding RNAs in eye emmetropization, the role of microRNAs (miRNAs) and other non-coding RNAs remains poorly understood. We performed a genome-wide analysis of the miRNA-mRNA gene regulatory networks underlying optical-defocus-induced myopia using massive parallel RNA sequencing (RNA-seq). Our analysis revealed a widespread involvement of miRNAs in optical defocus perception and visually guided eye emmetropization underlying myopia development. We found that a relatively small number of miRNAs (39 miRNAs total) regulate expression of over 450 mRNAs, or 59% of all mRNAs differentially expressed in the eyes of mice with optical-defocus-induced myopia. MiRNAs were also found to be involved in the regulation of the absolute majority of the biological processes and signaling pathways underlying visually guided eye emmetropization and myopia.
Project description:During postnatal development, the optical geometry of the eye is refined through a process called emmetropization. During eye emmetropization, optical defocus triggers a signaling cascade that originates in the retina, propagates across other ocular tissues and results in scleral wall remodeling. This signaling is associated with large-scale changes in gene expression, which was extensively studied at the mRNA level. Although several studies investigated the role of non-coding RNAs in eye emmetropization, the role of microRNAs (miRNAs) and other non-coding RNAs remains poorly understood. We performed a genome-wide analysis of the miRNA-mRNA gene regulatory networks underlying optical-defocus-induced myopia using massive parallel RNA sequencing (RNA-seq). Our analysis revealed a widespread involvement of miRNAs in optical defocus perception and visually guided eye emmetropization underlying myopia development. We found that a relatively small number of miRNAs (39 miRNAs total) regulate expression of over 450 mRNAs, or 59% of all mRNAs differentially expressed in the eyes of mice with optical-defocus-induced myopia. MiRNAs were also found to be involved in the regulation of the absolute majority of the biological processes and signaling pathways underlying visually guided eye emmetropization and myopia.
Project description:During postnatal development, the optical geometry of the eye is refined through a process called emmetropization. During eye emmetropization, optical defocus triggers a signaling cascade that originates in the retina, propagates across other ocular tissues and results in scleral wall remodeling. This signaling is associated with large-scale changes in gene expression, which was extensively studied at the mRNA level. Although several studies investigated the role of non-coding RNAs in eye emmetropization, the role of microRNAs (miRNAs) and other non-coding RNAs remains poorly understood. We performed a genome-wide analysis of the miRNA-mRNA gene regulatory networks underlying optical-defocus-induced myopia using massive parallel RNA sequencing (RNA-seq). Our analysis revealed a widespread involvement of miRNAs in optical defocus perception and visually guided eye emmetropization underlying myopia development. We found that a relatively small number of miRNAs (39 miRNAs total) regulate expression of over 450 mRNAs, or 59% of all mRNAs differentially expressed in the eyes of mice with optical-defocus-induced myopia. MiRNAs were also found to be involved in the regulation of the absolute majority of the biological processes and signaling pathways underlying visually guided eye emmetropization and myopia.
Project description:During postnatal development, the optical geometry of the eye is refined through a process called emmetropization. During eye emmetropization, optical defocus triggers a signaling cascade that originates in the retina, propagates across other ocular tissues and results in scleral wall remodeling. This signaling is associated with large-scale changes in gene expression, which was extensively studied at the mRNA level. Although several studies investigated the role of non-coding RNAs in eye emmetropization, the role of microRNAs (miRNAs) and other non-coding RNAs remains poorly understood. We performed a genome-wide analysis of the miRNA-mRNA gene regulatory networks underlying optical-defocus-induced myopia using massive parallel RNA sequencing (RNA-seq). Our analysis revealed a widespread involvement of miRNAs in optical defocus perception and visually guided eye emmetropization underlying myopia development. We found that a relatively small number of miRNAs (39 miRNAs total) regulate expression of over 450 mRNAs, or 59% of all mRNAs differentially expressed in the eyes of mice with optical-defocus-induced myopia. MiRNAs were also found to be involved in the regulation of the absolute majority of the biological processes and signaling pathways underlying visually guided eye emmetropization and myopia.
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:Development of myopia is associated with large-scale changes in ocular tissue gene expression. Although differential expression of coding genes underlying development of myopia has been a subject of intense investigation, the role of non-coding genes such as microRNAs in the development of myopia is largely unknown. In this study, we explored myopia-associated miRNA expression profiles in the retina and sclera of C57Bl/6J mice with experimentally induced myopia using microarray technology. We found a total of 53 differentially expressed miRNAs in the retina and no differences in miRNA expression in the sclera of C57BL/6J mice after 10 days of visual form deprivation, which induced -6.93 ± 2.44 D (p < 0.000001, n = 12) of myopia. We also identified their putative mRNA targets among mRNAs found to be differentially expressed in myopic retina and potential signaling pathways involved in the development of form-deprivation myopia using miRNA-mRNA interaction network analysis. Analysis of myopia-associated signaling pathways revealed that myopic response to visual form deprivation in the retina is regulated by a small number of highly integrated signaling pathways. Our findings highlight substantial involvement of miRNAs in the regulation of refractive eye development, and in the development of myopia through the retinal gene regulation.
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:To identify to identify target tissues and molecules involved with refractive myopic shift and axial length elongation in a murine lens-induced myopia model, we performed comprehensive analysis by microRNA array. Negative 30diptor (-30D) lens was fixed on right eye (-30D) of C57BL/6J mice (3weeks old, N=3) for 3 weeks, the refraction and the axial length were measured using a refractometer and a SD-OCT system in all eyes. Eye balls were enucleated and separated to cornea, iris, lens, retina, choroid and sclera. Total RNA was extracted from individual ocular components. MicroRNA expression analysis was carried out using Agilent Mouse miRNA Microarray (8×60K) miRBase21.0 (Agilent). Expression ratio calculation and miRNA varying expression were extracted by GeneSpring GX 14.5 (Agilent). After 3weeks of lens fixing, a refractive change and an axial length elongation change were observed (Normal vs -30D: 0.95 ± 1.85D vs -18.42 ± 3.98D, 0.155 mm ± 0.015mm vs 0.273 ± 0.009 mm), respectively. MiRNA expression changes that induced only by -30D lens fixing was confirmed in each part of the eyeball. By expression ratio calculation and miRNA varying expression analysis, upregulated miRNA (56 in cornea, 13 in iris, 6 in lens, 0 in retina, 29 in choroid and 30 in sclera) and downregulated miRNA (7 in cornea, 28 in iris, 17 in lens, 9 in retina, 7 in choroid and 40 in sclera) were observed. Overlapping miRNAs were also found while each eye tissues. In this study, miRNA varying expression were observed in each ocular part of the murine lens-induced myopia model. These miRNAs dysregulation may be functionally involved with the refractive myopia shift and the axial length elongation.
Project description:Juvenile primates develop myopia when their visual experience is degraded by lid fusion. In response to the abnormal visual input, retinal neural networks cause an excessive growth of the postequatorial segment of the eye, but the mechanism underlying this axial elongation is unknown. By combining analysis of gene expression, injection of the thymidine analog 5-bromo-2'-deoxyuridine and immunocytochemistry, we show that the retinal periphery in both juvenile rhesus macaques and green monkeys harbors a population of mitotically active neuroprogenitor cells that proliferate when the visual experience is altered by lid fusion. Furthermore, the number of dividing cells is highly correlated with the axial elongation of the eye and the resulting myopic refractive error. Thus, the retina undergoes active growth during the postnatal development of the primate eye. This growth is modulated by the visual input and accelerates considerably when the eye develops axial myopia. Keywords: disease state analysis