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An opsin 5–dopamine pathway mediates light-dependent vascular development in the eye
摘要： During mouse postnatal eye development, the embryonic hyaloid vascular network regresses from the vitreous as an adaption for high-acuity vision. This process occurs with precisely controlled timing. Here, we show that opsin 5 (OPN5; also known as neuropsin)-dependent retinal light responses regulate vascular development in the postnatal eye. In Opn5-null mice, hyaloid vessels regress precociously. We demonstrate that 380-nm light stimulation via OPN5 and VGAT (the vesicular GABA/glycine transporter) in retinal ganglion cells enhances the activity of inner retinal DAT (also known as SLC6A3; a dopamine reuptake transporter) and thus suppresses vitreal dopamine. In turn, dopamine acts directly on hyaloid vascular endothelial cells to suppress the activity of vascular endothelial growth factor receptor 2 (VEGFR2) and promote hyaloid vessel regression. With OPN5 loss of function, the vitreous dopamine level is elevated and results in premature hyaloid regression. These investigations identify violet light as a developmental timing cue that, via an OPN5–dopamine pathway, regulates optic axis clearance in preparation for visual function.
关键词： Hyaloid regression,Vascular development,Dopamine,VEGFR2,Light-dependent,Eye,Opsin 5,Retinal ganglion cells
更新于2025-11-21 11:20:42
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Improving Visual Field Examination of the Macula Using Structural Information
摘要： Purpose: To investigate a novel approach for structure-function modeling in glaucoma to improve visual field testing in the macula. Methods: We acquired data from the macular region in 20 healthy eyes and 31 with central glaucomatous damage. Optical coherence tomography (OCT) scans were used to estimate the local macular ganglion cell density. Perimetry was performed with a fundus-tracking device using a 10-2 grid. OCT scans were matched to the retinal image from the fundus perimeter to accurately map the tested locations onto the structural damage. Binary responses from the subjects to all presented stimuli were used to calculate the structure-function model used to generate prior distributions for a ZEST (Zippy Estimation by Sequential Testing) Bayesian strategy. We used simulations based on structural and functional data acquired from an independent dataset of 20 glaucoma patients to compare the performance of this new strategy, structural macular ZEST (MacS-ZEST), with a standard ZEST. Results: Compared to the standard ZEST, MacS-ZEST reduced the number of presentations by 13% in reliable simulated subjects and 14% with higher rates (≥20%) of false positive or false negative errors. Reduction in mean absolute error was not present for reliable subjects but was gradually more important with unreliable responses (≥10% at 30% error rate). Conclusions: Binary responses can be modeled to incorporate detailed structural information from macular OCT into visual field testing, improving overall speed and accuracy in poor responders. Translational Relevance: Structural information can improve speed and reliability for macular testing in glaucoma practice.
关键词： glaucoma,ganglion cells,optical coherence tomography,perimetry,visual field
更新于2025-09-23 15:23:52
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Retinal Neuroprotection From Optic Nerve Trauma by Deletion of Arginase 2
摘要： Our previous studies have implicated expression of the mitochondrial isoform of the arginase enzyme arginase 2 (A2) in neurovascular injury during ischemic retinopathies. The aim of this study was to characterize the specific involvement of A2 in retinal injury following optic nerve crush (ONC). To accomplish this, wild-type (WT) or A2 knockout (A2?/?) mice were subjected to ONC injury. The contralateral eye served as sham control. Quantitative RT-PCR and western blot were used to evaluate mRNA and protein expression. Retinal ganglion cell (RGC) survival was assessed in retinal whole mounts. Axonal sprouting was determined by anterograde transport of Cholera Toxin B (CTB). These analyses showed increased A2 expression following ONC. Numbers of NeuN-positive neurons as well as Brn3a- and RBPMS-positive RGC were decreased in the WT retinas at 14 days after ONC as compared to the sham controls. This ONC-induced neuronal loss was diminished in the A2?/? retinas. Similarly, axonal degeneration was ameliorated by A2 deletion whereas axon sprouting was enhanced. Significant retinal thinning was also seen in WT retinas at 21 days after ONC, and this was blocked in A2?/? mice. Cell death studies showed an increase in TUNEL positive cells in the RGC layer at 5 days after ONC in the WT retinas, and this was attenuated by A2 deletion. ONC increased glial cell activation in WT retinas, and this was significantly reduced by A2 deletion. Western blotting showed a marked increase in the neurotrophin, brain derived neurotrophic factor (BDNF) and its downstream signaling in A2?/? retinas vs. WT after ONC. This was associated with increases in the axonal regeneration marker GAP-43 in A2?/? retinas. Furthermore, A2?/? retinas showed decreased NLRP3 inflammasome activation and lower interleukin (IL-) 1β/IL-18 levels as compared to WT retinas subjected to ONC. Collectively, our results show that deletion of A2 limits ONC-induced neurodegeneration and glial activation, and enhances axonal sprouting by a mechanism involving increases in BDNF and decreases in retinal inflammation. These data demonstrate that A2 plays an important role in ONC-induced retinal damage. Blockade of A2 activity may offer a therapeutic strategy for preventing vision loss induced by traumatic retinal injury.
关键词： optic nerve crush,retinal ganglion cells,retina,brain derived neurotrophic factor,neuroprotection,arginase 2
更新于2025-09-23 15:23:52
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Polybenzyl Glutamate Biocompatible Scaffold Promotes the Efficiency of Retinal Differentiation toward Retinal Ganglion Cell Lineage from Human-Induced Pluripotent Stem Cells
摘要： Optic neuropathy is one of the leading causes of irreversible blindness caused by retinal ganglion cell (RGC) degeneration. The development of induced pluripotent stem cell (iPSC)-based therapy opens a therapeutic window for RGC degeneration, and tissue engineering may further promote the efficiency of differentiation process of iPSCs. The present study was designed to evaluate the effects of a novel biomimetic polybenzyl glutamate (PBG) scaffold on culturing iPSC-derived RGC progenitors. The iPSC-derived neural spheres cultured on PBG scaffold increased the differentiated retinal neurons and promoted the neurite outgrowth in the RGC progenitor layer. Additionally, iPSCs cultured on PBG scaffold formed the organoid-like structures compared to that of iPSCs cultured on cover glass within the same culture period. With RNA-seq, we found that cells of the PBG group were differentiated toward retinal lineage and may be related to the glutamate signaling pathway. Further ontological analysis and the gene network analysis showed that the differentially expressed genes between cells of the PBG group and the control group were mainly associated with neuronal differentiation, neuronal maturation, and more specifically, retinal differentiation and maturation. The novel electrospinning PBG scaffold is beneficial for culturing iPSC-derived RGC progenitors as well as retinal organoids. Cells cultured on PBG scaffold differentiate effectively and shorten the process of RGC differentiation compared to that of cells cultured on coverslip. The new culture system may be helpful in future disease modeling, pharmacological screening, autologous transplantation, as well as narrowing the gap to clinical application.
关键词： induced pluripotent stem cells,retinal ganglion cells,tissue engineering,glaucoma,optic neuropathy,polybenzyl glutamate,electrospinning scaffold
更新于2025-09-23 15:22:29
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[IEEE 2018 25th IEEE International Conference on Image Processing (ICIP) - Athens, Greece (2018.10.7-2018.10.10)] 2018 25th IEEE International Conference on Image Processing (ICIP) - A Retina-Inspired Encoder: An Innovative Step on Image Coding Using Leaky Integrate-and-Fire Neurons
摘要： This paper aims to build an image coding system based on a model of the mammalian retina. The retina is the light-sensitive layer of tissue located on the inner coat of the eye and it is responsible for vision. Inspired by the way the retina handles and compresses visual information and based on previous studies we aim to build and analytically study a retinal-inspired image quantizer, based on the Leaky Integrate-and-Fire (LIF) model, a neural model approximating the behavior of the ganglion cells of the Ganglionic retinal layer that is responsible for visual data compression. In order to have a more concrete view of the encoder's behavior, in our experiments, we make use of the spatiotemporal decomposition layers provided by extensive studies on a previous retinal layer, the Outer Plexiform Layer (OPL). The decomposition layers produced by the OPL, are being encoded using our LIF image encoder and then, they are reconstructed to observe the encoder's efficiency.
关键词： weighted difference of Gaussians,neural coding,Leaky Integrate-and-Fire (LIF) model,Ganglion cells,image coding,Retina
更新于2025-09-23 15:22:29
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Amplitude Modulation-based Electrical Stimulation for Encoding Multipixel Spatiotemporal Visual Information in Retinal Neural Activities
摘要： Retinal implants have been developed as a promising way to restore partial vision for the blind. The observation and analysis of neural activities can offer valuable insights for successful prosthetic electrical stimulation. Retinal ganglion cell (RGC) activities have been investigated to provide knowledge on the requirements for electrical stimulation, such as threshold current and the effect of stimulation waveforms. To develop a detailed 'stimulation strategy' for faithful delivery of spatiotemporal visual information to the brain, it is essential to examine both the temporal and spatial characteristics of RGC responses, whereas previous studies were mainly focused on one or the other. In this study, we investigate whether the spatiotemporal visual information can be decoded from the RGC network activity evoked by patterned electrical stimulation. Along with a thorough characterization of spatial spreading of stimulation current and temporal information encoding, we demonstrated that multipixel spatiotemporal visual information can be accurately decoded from the population activities of RGCs stimulated by amplitude-modulated pulse trains. We also found that the details of stimulation, such as pulse amplitude range and pulse rate, were crucial for accurate decoding. Overall, the results suggest that useful visual function may be restored by amplitude modulation-based retinal stimulation.
关键词： Degenerated Retina,Electrical Stimulation,Retinal Ganglion Cells,Retinal Implant,Spike Train Decoding,Microelectrode Array
更新于2025-09-23 15:22:29
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Different Effect of Sox11 in Retinal Ganglion Cells Survival and Axon Regeneration
摘要： Purpose: The present study examines the role of Sox11 in the initial response of retinal ganglion cells (RGCs) to axon damage and in optic nerve regeneration in mouse. Methods: Markers of retinal injury were identified using the normal retina database and optic nerve crush (ONC) database on GeneNetwork2 (www.genenetwork.org). One gene, Sox11, was highly upregulated following ONC. We examined the role of this transcription factor, Sox11, following ONC and optic nerve regeneration in mice. In situ hybridization was performed using the Affymetrix 2-plex Quantigene View RNA In Situ Hybridization Tissue Assay System. Sox11 was partially knocked out by intravitreal injection of AAV2-CMV-Cre-GFP in Sox11f/f mice. Optic nerve regeneration model used Pten knockdown. Mice were perfused and the retinas and optic nerves were dissected and examined for RGC survival and axon growth. Results: Sox11 was dramatically upregulated in the retina following ONC injury. The level of Sox11 message increased by approximately eightfold 2 days after ONC. In situ hybridization demonstrated low-level Sox11 message in RGCs and cells in the inner nuclear layer in the normal retina as well as a profound increase in Sox11 message within the ganglion cells following ONC. In Sox11f/f retinas, partially knocking out Sox11 significantly increased RGC survival after ONC as compared to the AAV2-CMV-GFP control group; however, it had little effect on the ability of axon regeneration. Combinatorial downregulation of both Sox11 and Pten resulted in a significant increase in RGC survival as compared to Pten knockdown only. When Pten was knocked down there was a remarkable increase in the number and the length of regenerating axons. Partially knocking out Sox11 in combination with Pten deletion resulted in a fewer regenerating axons. Conclusion: Taken together, these data demonstrate that Sox11 is involved in the initial response of the retina to injury, playing a role in the early attempts of axon regeneration and neuronal survival. Downregulation of Sox11 aids in RGC survival following injury of optic nerve axons, while a partial knockout of Sox11 negates the axon regeneration stimulated by Pten knockdown.
关键词： optic nerve crush,AAV2,retinal ganglion cells,axon regeneration,Sox11
更新于2025-09-23 15:22:29
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Non-parametric Physiological Classification of Retinal Ganglion Cells in the Mouse Retina
摘要： Retinal ganglion cells, the sole output neurons of the retina, exhibit surprising diversity. A recent study reported over 30 distinct types in the mouse retina, indicating that the processing of visual information is highly parallelised in the brain. The advent of high density multi-electrode arrays now enables recording from many hundreds to thousands of neurons from a single retina. Here we describe a method for the automatic classification of large-scale retinal recordings using a simple stimulus paradigm and a spike train distance measure as a clustering metric. We evaluate our approach using synthetic spike trains, and demonstrate that major known cell types are identified in high-density recording sessions from the mouse retina with around 1,000 retinal ganglion cells. A comparison across different retinas reveals substantial variability between preparations, suggesting pooling data across retinas should be approached with caution. As a parameter-free method, our approach is broadly applicable for cellular physiological classification in all sensory modalities.
关键词： classification,retinal ganglion cells,light responses,spike distance,multi-electrode array
更新于2025-09-23 15:22:29
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SIRT6 protects retinal ganglion cells against hydrogen peroxide-induced apoptosis and oxidative stress by promoting Nrf2/ARE signaling via inhibition of Bach1
摘要： Oxidative stress-induced damage of retinal ganglion cells (RGCs) is a major contributor to retinal degenerative diseases, such as glaucoma. Sirtuin 6 (SIRT6) has emerged as a cytoprotective protein against various insults. However, whether SIRT6 exerts a protective effect against oxidative stress-damaged RGCs remains unknown. In this study, we aimed to investigate the potential role and regulatory mechanism of SIRT6 in hydrogen peroxide (H2O2)-induced oxidative damage of RGCs in vitro. We found that SIRT6 expression was significantly downregulated in RGCs with H2O2 treatment. Functional experiments showed that overexpression of SIRT6 improved survival and reduced apoptosis and the production of reactive oxygen species (ROS) in H2O2-treated RGCs. In contrast, SIRT6 knockdown had the opposite effect. Moreover, we found that SIRT6 overexpression promoted the nuclear accumulation of nuclear factor erythroid 2-related factor 2 (Nrf2) and increased the activity of antioxidant response element (ARE). In addition, we found that the promotional effect of SIRT6 on Nrf2/ARE signaling was associated with inhibition of BTB and CNC homology 1 (Bach1), an inhibitor of Nrf2. However, overexpression of Bach1 or inhibition of Nrf2/ARE signaling partially reversed the SIRT6-mediated protective effect. Taken together, these results demonstrate that SIRT6 protects RGCs from oxidative stress-induced damage by promoting the activation of Nrf2/ARE signaling via inhibition of Bach1, suggesting a potential role of SIRT6 in retinal degenerative diseases.
关键词： Nrf2,SIRT6,retinal ganglion cells,Bach1.
更新于2025-09-23 15:22:29
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Activation of Nrf2/HO-1 pathway protects retinal ganglion cells from a rat chronic ocular hypertension model of glaucoma
摘要： Objective The objective of this work was to find out the effects of nuclear factor erythroid 2-related factor/heme oxygenase-1 (Nrf2/HO-1) pathway on retinal ganglion cell (RGC) injury in glaucoma. Methods The chronic ocular hypertension (COH) rat models of glaucoma were constructed, and intraocular pressure (IOP) and RGC numbers were detected at different time points. Additionally, rats were divided into normal group (normal control rats), model group (COH model rats), and model + tBHQ group (COH model rats treated with Nrf activator, tBHQ). RGC apoptosis was detected by using TUNEL staining, and the expressions of Nrf2/HO-1 were detected by qRT-PCR and western blotting. Results COH model rats showed significant IOP elevation and the increased mRNA and protein expressions of Nrf2 and HO-1 from 1 to 6 weeks after operation, with the evidently decreased RGC numbers at 4 weeks and 6 weeks after operation (all P < 0.05). Besides, rats in the model group had increased apoptosis index (AI) of RGCs and the elevated mRNA and protein expressions of Nrf2/HO-1 with remarkably reduced RGC numbers when compared with normal control rats, but the model rats treated with tBHQ exhibited an apparent decrease in AI of RGCs, as well as remarkable increases in RGC numbers and the mRNA and protein expression of Nrf2/HO-1 (all P < 0.05). Conclusion Activation of Nrf2/HO-1 pathway significantly reduced the apoptosis and injury of RGCs in rats with chronic ocular hypertension (COH), thereby protecting RGCs in glaucoma, which could be a promising clinical target to prevent RGC degeneration in glaucoma.
关键词： Apoptosis,Nrf2/HO-1 pathway,Glaucoma,Retinal ganglion cells
更新于2025-09-23 15:22:29