RESUMEN

The retinal fovea in human and nonhuman primates is essential for high acuity and color vision. Within the fovea lies specialized circuitry in which signals from a single cone photoreceptor are largely conveyed to one ON and one OFF type midget bipolar cell (MBC), which in turn connect to a single ON or OFF midget ganglion cell (MGC), respectively. Restoring foveal vision requires not only photoreceptor replacement but also appropriate reconnection with surviving ON and OFF MBCs and MGCs. However, our current understanding of the effects of cone loss on the remaining foveal midget pathway is limited. We thus used serial block-face electron microscopy to determine the degree of plasticity and potential remodeling of this pathway in adult Macaca fascicularis several months after acute photoreceptor loss upon photocoagulation. We reconstructed MBC structure and connectivity within and adjacent to the region of cone loss. We found that MBC dendrites within the scotoma retracted and failed to reach surviving cones to form new connections. However, both surviving cones and ON and OFF MBC dendrites at the scotoma border exhibited remodeling, suggesting that these neurons can demonstrate plasticity and rewiring at maturity. At six months postlesion, disconnected OFF MBCs clearly lost output ribbon synapses with their postsynaptic partners, whereas the majority of ON MBCs maintained their axonal ribbon numbers, suggesting differential timing or extent in ON and OFF midget circuit remodeling after cone loss. Our findings raise rewiring considerations for cell replacement approaches in the restoration of foveal vision.

Asunto(s)

Fóvea Central , Macaca fascicularis , Células Bipolares de la Retina , Células Fotorreceptoras Retinianas Conos , Animales , Células Fotorreceptoras Retinianas Conos/metabolismo , Células Fotorreceptoras Retinianas Conos/patología , Células Bipolares de la Retina/metabolismo , Células Bipolares de la Retina/fisiología , Células Ganglionares de la Retina/fisiología , Células Ganglionares de la Retina/patología , Plasticidad Neuronal/fisiología , Dendritas/fisiología , Vías Visuales , Masculino

RESUMEN

Purpose: Retinitis pigmentosa (RP), the most common inherited retinal disease, is characterized by progressive photoreceptor degeneration. It remains unknown to what extent surviving photoreceptors transduce light and support vision in RP. To address this, we correlated structure and functional measures using adaptive optics scanning laser ophthalmoscopy (AOSLO), adaptive optics microperimetry, and adaptive optics optical coherence tomography (AO-OCT)-based optoretinograms (ORGs). Methods: Four patients with RP were imaged with AOSLO across the visual field covering the transition zone (TZ) of normal to diseased retina. Cone density was estimated in discrete regions spanning the TZ. Visual sensitivity was assessed by measuring increment thresholds for a 3-arcmin stimulus targeted via active eye tracking in AOSLO. ORGs were measured at the same locations using AO-OCT to assess the cones' functional response to a 528 ± 20-nm stimulus. Individual cone outer segment (COS) lengths were measured from AO-OCT in each subject. Results: Cone density was significantly reduced in patients with RP. Density reduction correlated with TZ location in 3 patients with RP, while a fourth had patches of reduced density throughout the retina. ORG amplitude was reduced in regions of normal and reduced cone density in all patients with RP. ORG response and COS length were positively correlated in controls but not in patients with RP. Despite deficits in cone density and ORG, visual sensitivity remained comparable to controls in three of four patients with RP. Conclusions: ORG-based measures of retinal dysfunction may precede deficits in cone structure and visual sensitivity. ORG is a sensitive measure of RP disease status and has significant potential to provide insight into disease progression and treatment efficacy.

Asunto(s)

Oftalmoscopía , Células Fotorreceptoras Retinianas Conos , Retinitis Pigmentosa , Tomografía de Coherencia Óptica , Agudeza Visual , Pruebas del Campo Visual , Campos Visuales , Humanos , Retinitis Pigmentosa/fisiopatología , Retinitis Pigmentosa/diagnóstico , Tomografía de Coherencia Óptica/métodos , Células Fotorreceptoras Retinianas Conos/patología , Células Fotorreceptoras Retinianas Conos/fisiología , Oftalmoscopía/métodos , Masculino , Femenino , Pruebas del Campo Visual/métodos , Adulto , Agudeza Visual/fisiología , Campos Visuales/fisiología , Persona de Mediana Edad , Imagen Multimodal , Recuento de Células

RESUMEN

Microglia are resident immune cells in the central nervous system, including the retina that surveil the environment for damage and infection. Following retinal damage, microglia undergo morphological changes, migrate to the site of damage, and express and secrete pro-inflammatory signals. In the zebrafish retina, inflammation induces the reprogramming and proliferation of Müller glia and the regeneration of neurons following damage or injury. Immunosuppression or pharmacological ablation of microglia reduce or abolish Müller glia proliferation. We evaluated the retinal architecture and retinal regeneration in adult zebrafish irf8 mutants, which have significantly depleted numbers of microglia. We show that irf8 mutants have normal retinal structure at 3 months post fertilization (mpf) and 6 mpf but fewer cone photoreceptors by 10 mpf. Surprisingly, light-induced photoreceptor ablation induced Müller glia proliferation in irf8 mutants and cone and rod photoreceptor regeneration. Light-damaged retinas from both wild-type and irf8 mutants show upregulated expression of mmp-9, il8, and tnfß pro-inflammatory cytokines. Our data demonstrate that adult zebrafish irf8 mutants can regenerate normally following acute retinal injury. These findings suggest that microglia may not be essential for retinal regeneration in zebrafish and that other mechanisms can compensate for the reduction in microglia numbers.

Asunto(s)

Factores Reguladores del Interferón , Microglía , Retina , Pez Cebra , Animales , Factores Reguladores del Interferón/metabolismo , Factores Reguladores del Interferón/genética , Microglía/metabolismo , Retina/metabolismo , Retina/patología , Mutación , Regeneración , Proteínas de Pez Cebra/genética , Proteínas de Pez Cebra/metabolismo , Células Fotorreceptoras Retinianas Conos/metabolismo , Células Fotorreceptoras Retinianas Conos/patología , Células Fotorreceptoras de Vertebrados/metabolismo , Células Fotorreceptoras de Vertebrados/patología , Proliferación Celular , Luz , Células Ependimogliales/metabolismo , Células Ependimogliales/patología

RESUMEN

Cone photoreceptor cyclic nucleotide-gated (CNG) channels play an essential role in phototransduction and cellular Ca2+ homeostasis. Mutations in genes encoding the channel subunits CNGA3 and CNGB3 are associated with achromatopsia, progressive cone dystrophy, and early-onset macular degeneration. Cone loss in patients with achromatopsia and cone dystrophy associated with CNG channel mutations has been documented by optical coherence tomography and in mouse models of CNG channel deficiency. Cone death in CNG channel-deficient retinas involves endoplasmic reticulum (ER) stress-associated apoptosis, dysregulation of cellular/ER Ca2+ homeostasis, impaired protein folding/processing, and impaired ER-associated degradation (ERAD). The E3 ubiquitin-protein ligase synoviolin 1 (SYVN1) is the primary component of the SYVN1/SEL1L ER retrotranslocon responsible for ERAD. Previous studies have shown that manipulations that protect cones and reduce ER stress/cone death in CNG channel deficiency, such as increasing ER Ca2+ preservation or treatment with an ER chaperone, increase the expression of SYVN1 and other components of the ER retrotranslocon. The present work investigated the effects of SYVN1 overexpression. Intraocular injection of AAV5-IRBP/GNAT2-Syvn1 resulted in overexpression of SYVN1 in cones of CNG channel-deficient mice. Following treatment, cone density in Cnga3-/- mice was significantly increased, compared with untreated controls, outer segment localization of cone opsin was improved, and ER stress/apoptotic cell death was reduced. Overexpression of SYVN1 also led to increased expression levels of the retrotranslocon components, degradation in ER protein 1 (DERL1), ERAD E3 ligase adaptor subunit (SEL1L), and homocysteine inducible ER protein with ubiquitin-like domain 1 (HERPUD1). Moreover, overexpression of SYVN1 likely enhanced protein ubiquitination/proteasome degradation in CNG channel-deficient retinas. This study demonstrates the role of SYVN1/ERAD in cone preservation in CNG channel deficiency and supports the strategy of promoting ERAD for cone protection.

Asunto(s)

Canales Catiónicos Regulados por Nucleótidos Cíclicos , Estrés del Retículo Endoplásmico , Retículo Endoplásmico , Células Fotorreceptoras Retinianas Conos , Ubiquitina-Proteína Ligasas , Animales , Ubiquitina-Proteína Ligasas/genética , Ubiquitina-Proteína Ligasas/metabolismo , Células Fotorreceptoras Retinianas Conos/metabolismo , Células Fotorreceptoras Retinianas Conos/patología , Ratones , Retículo Endoplásmico/metabolismo , Canales Catiónicos Regulados por Nucleótidos Cíclicos/genética , Canales Catiónicos Regulados por Nucleótidos Cíclicos/metabolismo , Degradación Asociada con el Retículo Endoplásmico , Ratones Noqueados , Ratones Endogámicos C57BL

RESUMEN

Inherited retinal diseases, which include retinitis pigmentosa, are a family of genetic disorders characterized by gradual rod-cone degeneration and vision loss, without effective pharmacological treatments. Experimental approaches aim to delay disease progression, supporting cones' survival, crucial for human vision. Histone deacetylases (HDACs) mediate the activation of epigenetic and nonepigenetic pathways that modulate cone degeneration in RP mouse models. We developed new HDAC inhibitors (5a-p), typified by a tetrahydro-γ-carboline scaffold, characterized by high HDAC6 inhibition potency with balanced physicochemical properties for in vivo studies. Compound 5d (repistat, IC50 HDAC6 = 6.32 nM) increased the levels of acetylated α-tubulin compared to histone H3 in ARPE-19 and 661W cells. 5d promoted vision rescue in the atp6v0e1-/- zebrafish model of photoreceptor dysfunction. A single intravitreal injection of 5d in the rd10 mouse model of RP supported morphological and functional preservation of cone cells and maintenance of the retinal pigment epithelium array.

Asunto(s)

Inhibidores de Histona Desacetilasas , Células Fotorreceptoras Retinianas Conos , Pez Cebra , Animales , Células Fotorreceptoras Retinianas Conos/metabolismo , Células Fotorreceptoras Retinianas Conos/efectos de los fármacos , Células Fotorreceptoras Retinianas Conos/patología , Humanos , Ratones , Inhibidores de Histona Desacetilasas/farmacología , Inhibidores de Histona Desacetilasas/química , Inhibidores de Histona Desacetilasas/uso terapéutico , Retinitis Pigmentosa/metabolismo , Retinitis Pigmentosa/tratamiento farmacológico , Retinitis Pigmentosa/patología , Histona Desacetilasas/metabolismo , Histona Desacetilasa 6/antagonistas & inhibidores , Histona Desacetilasa 6/metabolismo , Supervivencia Celular/efectos de los fármacos , Modelos Animales de Enfermedad , Relación Estructura-Actividad

RESUMEN

Inherited retinopathies are devastating diseases that in most cases lack treatment options. Disease-modifying therapies that mitigate pathophysiology regardless of the underlying genetic lesion are desirable due to the diversity of mutations found in such diseases. We tested a systems pharmacology-based strategy that suppresses intracellular cAMP and Ca2+ activity via G protein-coupled receptor (GPCR) modulation using tamsulosin, metoprolol, and bromocriptine coadministration. The treatment improves cone photoreceptor function and slows degeneration in Pde6ßrd10 and RhoP23H/WT retinitis pigmentosa mice. Cone degeneration is modestly mitigated after a 7-month-long drug infusion in PDE6A-/- dogs. The treatment also improves rod pathway function in an Rpe65-/- mouse model of Leber congenital amaurosis but does not protect from cone degeneration. RNA-sequencing analyses indicate improved metabolic function in drug-treated Rpe65-/- and rd10 mice. Our data show that catecholaminergic GPCR drug combinations that modify second messenger levels via multiple receptor actions provide a potential disease-modifying therapy against retinal degeneration.

Asunto(s)

Modelos Animales de Enfermedad , Reposicionamiento de Medicamentos , Retinitis Pigmentosa , Animales , Ratones , Perros , Retinitis Pigmentosa/tratamiento farmacológico , Retinitis Pigmentosa/genética , Mutación , Fosfodiesterasas de Nucleótidos Cíclicos Tipo 6/genética , Fosfodiesterasas de Nucleótidos Cíclicos Tipo 6/metabolismo , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/metabolismo , Ratones Noqueados , Amaurosis Congénita de Leber/tratamiento farmacológico , Amaurosis Congénita de Leber/genética , Bromocriptina/farmacología , Bromocriptina/uso terapéutico , cis-trans-Isomerasas/genética , cis-trans-Isomerasas/metabolismo , Humanos , Quimioterapia Combinada , Ratones Endogámicos C57BL , Células Fotorreceptoras Retinianas Conos/efectos de los fármacos , Células Fotorreceptoras Retinianas Conos/metabolismo , Células Fotorreceptoras Retinianas Conos/patología , Femenino , AMP Cíclico/metabolismo , Degeneración Retiniana/tratamiento farmacológico , Degeneración Retiniana/genética , Masculino , Calcio/metabolismo

RESUMEN

BACKGROUND: Iron-induced oxidative stress was thought to be the reason why the a-wave amplitude of the electroretinogram (ERG) dropped when iron ions were present. It is assumed that reactive oxygen species (ROS) are generated in the presence of iron ions, and this leads to a decrease in hyperpolarization of the photoreceptor. It is known that in age-related macular degeneration (AMD), sodium iodate can induce oxidative stress, apoptosis, and retinal damage, which mimic the effects of clinical AMD. Here, the reduction of the a-wave amplitude in mice with sodium iodate-induced age-related macular degeneration is explained. METHODS: The leading edge of the a-wave is divided into voltages developed by cones and rods. The same oxidative stress model is applied here since sodium iodate causes the creation of ROS in a manner similar to that caused by iron ions, with the exception that the retina is treated as a circuit of various resistances when computing the photoresponse. Moreover, sodium iodate also leads to apoptosis and, hence, may cause misalignment in cones (not in rods) during the initial stage of apoptosis in AMD. To include the effects of apoptosis and shortening in cones and rods, we have used a factor representing the fraction of total cones and rods that are alive. To include the effect of misalignment of cones on the reduction of the a-wave amplitude, we have used the Stiles-Crawford function to calculate the number of photoisomerizations occurring in a photoreceptor misaligned at an angle θ. The results are compared with experimental data. RESULTS: In sodium iodate-treated eyes, the ROS produced can attract calcium ions in the photoreceptor, which increases the calcium influx. In the case of the cones, the inclusion of the misalignment angle in the phototransduction process helps in determining the voltage and slope of the voltage vs. time graph.The smaller the fraction of active photoreceptors, the smaller the amplitude of the a-wave. The calcium influx, misaligned photoreceptors, and total photoreceptor loss all cause the amplitude of the a-wave to decrease, and at any time from the beginning of phototransduction cascade, the calcium influx causes the slope of the a-wave to increase. CONCLUSION: The reduction in the a-wave amplitude in the eyes of sodium iodate-treated mice is attributed to oxidative stress in both cones and rods and cone misalignment, which ultimately lead to apoptosis and vision loss in AMD.

Asunto(s)

Electrorretinografía , Yodatos , Degeneración Macular , Estrés Oxidativo , Especies Reactivas de Oxígeno , Células Fotorreceptoras Retinianas Conos , Animales , Degeneración Macular/patología , Degeneración Macular/fisiopatología , Degeneración Macular/inducido químicamente , Ratones , Estrés Oxidativo/efectos de los fármacos , Especies Reactivas de Oxígeno/metabolismo , Células Fotorreceptoras Retinianas Conos/efectos de los fármacos , Células Fotorreceptoras Retinianas Conos/patología , Células Fotorreceptoras Retinianas Conos/metabolismo , Apoptosis/efectos de los fármacos , Células Fotorreceptoras Retinianas Bastones/efectos de los fármacos , Células Fotorreceptoras Retinianas Bastones/patología , Células Fotorreceptoras Retinianas Bastones/metabolismo , Modelos Animales de Enfermedad , Modelos Biológicos

RESUMEN

Inherited cone disorders (ICDs) are a heterogeneous sub-group of inherited retinal disorders (IRDs), the leading cause of sight loss in children and working-age adults. ICDs result from the dysfunction of the cone photoreceptors in the macula and manifest as the loss of colour vision and reduced visual acuity. Currently, 37 genes are associated with varying forms of ICD; however, almost half of all patients receive no molecular diagnosis. This review will discuss the known ICD genes, their molecular function, and the diseases they cause, with a focus on the most common forms of ICDs, including achromatopsia, progressive cone dystrophies (CODs), and cone-rod dystrophies (CORDs). It will discuss the gene-specific therapies that have emerged in recent years in order to treat patients with some of the more common ICDs.

Asunto(s)

Defectos de la Visión Cromática , Distrofias de Conos y Bastones , Células Fotorreceptoras Retinianas Conos , Humanos , Defectos de la Visión Cromática/genética , Distrofias de Conos y Bastones/genética , Células Fotorreceptoras Retinianas Conos/patología , Células Fotorreceptoras Retinianas Conos/metabolismo , Distrofia del Cono/genética , Ceguera/genética , Animales , Terapia Genética/métodos

RESUMEN

This review examines the pivotal role of photoreceptor cells in ocular refraction development, focusing on dopamine (DA) as a key neurotransmitter. Contrary to the earlier view favoring cone cells, recent studies have highlighted the substantial contributions of both rod and cone cells to the visual signaling pathways that influence ocular refractive development. Notably, rod cells appeared to play a central role. Photoreceptor cells interact intricately with circadian rhythms, color vision pathways, and other neurotransmitters, all of which are crucial for the complex mechanisms driving the development of myopia. This review emphasizes that ocular refractive development results from a coordinated interplay between diverse cell types, signaling pathways, and neurotransmitters. This perspective has significant implications for unraveling the complex mechanisms underlying myopia and aiding in the development of more effective prevention and treatment strategies.

Asunto(s)

Miopía , Refracción Ocular , Miopía/fisiopatología , Miopía/metabolismo , Miopía/etiología , Humanos , Refracción Ocular/fisiología , Animales , Dopamina/metabolismo , Células Fotorreceptoras Retinianas Conos/fisiología , Células Fotorreceptoras Retinianas Conos/patología , Células Fotorreceptoras Retinianas Bastones/fisiología , Ritmo Circadiano/fisiología , Transducción de Señal/fisiología , Células Fotorreceptoras de Vertebrados/fisiología , Células Fotorreceptoras de Vertebrados/patología

RESUMEN

Glyburide, a sulfonylurea drug used to treat type 2 diabetes, boasts neuroprotective effects by targeting the sulfonylurea receptor 1 (SUR1) and associated ion channels in various cell types, including those in the central nervous system and the retina. Previously, we demonstrated that glyburide therapy improved retinal function and structure in a rat model of diabetic retinopathy. In the present study, we explore the application of glyburide in non-neovascular ("dry") age-related macular degeneration (AMD), another progressive disease characterized by oxidative stress-induced damage and neuroinflammation that trigger cell death in the retina. We show that glyburide administration to a human cone cell line confers protection against oxidative stress, inflammasome activation, and apoptosis. To corroborate our in vitro results, we also conducted a case-control study, controlling for AMD risk factors and other diabetes medications. It showed that glyburide use in patients reduces the odds of new-onset dry AMD. A positive dose-response relationship is observed from this analysis, in which higher cumulative doses of glyburide further reduce the odds of new-onset dry AMD. In the quest for novel therapies for AMD, glyburide emerges as a promising repurposable drug given its known safety profile. The results from this study provide insights into the multifaceted actions of glyburide and its potential as a neuroprotective agent for retinal diseases; however, further preclinical and clinical studies are needed to validate its therapeutic potential in the context of degenerative retinal disorders such as AMD.

Asunto(s)

Gliburida , Degeneración Macular , Fármacos Neuroprotectores , Estrés Oxidativo , Humanos , Gliburida/farmacología , Gliburida/uso terapéutico , Degeneración Macular/tratamiento farmacológico , Degeneración Macular/prevención & control , Fármacos Neuroprotectores/uso terapéutico , Fármacos Neuroprotectores/farmacología , Estrés Oxidativo/efectos de los fármacos , Masculino , Femenino , Apoptosis/efectos de los fármacos , Anciano , Línea Celular , Estudios de Casos y Controles , Células Fotorreceptoras Retinianas Conos/efectos de los fármacos , Células Fotorreceptoras Retinianas Conos/patología , Neuroprotección/efectos de los fármacos , Inflamasomas/metabolismo , Inflamasomas/efectos de los fármacos

RESUMEN

Animal models of retinal degeneration are critical for understanding disease and testing potential therapies. Inducing degeneration commonly involves the administration of chemicals that kill photoreceptors by disrupting metabolic pathways, signaling pathways, or protein synthesis. While chemically induced degeneration has been demonstrated in a variety of animals (mice, rats, rabbits, felines, 13-lined ground squirrels (13-LGS), pigs, chicks), few studies have used noninvasive high-resolution retinal imaging to monitor the in vivo cellular effects. Here, we used longitudinal scanning light ophthalmoscopy (SLO), optical coherence tomography, and adaptive optics SLO imaging in the euthermic, cone-dominant 13-LGS (46 animals, 52 eyes) to examine retinal structure following intravitreal injections of chemicals, which were previously shown to induce photoreceptor degeneration, throughout the active season of 2019 and 2020. We found that iodoacetic acid induced severe pan-retinal damage in all but one eye, which received the lowest concentration. While sodium nitroprusside successfully induced degeneration of the outer retinal layers, the results were variable, and damage was also observed in 50% of contralateral control eyes. Adenosine triphosphate and tunicamycin induced outer retinal specific damage with varying results, while eyes injected with thapsigargin did not show signs of degeneration. Given the variability of damage we observed, follow-up studies examining the possible physiological origins of this variability are critical. These additional studies should further advance the utility of chemically induced photoreceptor degeneration models in the cone-dominant 13-LGS.

Asunto(s)

Células Fotorreceptoras Retinianas Conos , Degeneración Retiniana , Sciuridae , Tomografía de Coherencia Óptica , Animales , Degeneración Retiniana/inducido químicamente , Degeneración Retiniana/patología , Células Fotorreceptoras Retinianas Conos/patología , Células Fotorreceptoras Retinianas Conos/efectos de los fármacos , Modelos Animales de Enfermedad , Inyecciones Intravítreas , Oftalmoscopía , Nitroprusiato/farmacología , Femenino , Masculino

RESUMEN

Retinitis pigmentosa (RP) is an inherited retinal disease in which there is a loss of cone-mediated daylight vision. As there are >100 disease genes, our goal is to preserve cone vision in a disease gene-agnostic manner. Previously we showed that overexpressing TXNIP, an α-arrestin protein, prolonged cone vision in RP mouse models, using an AAV to express it only in cones. Here, we expressed different alleles of Txnip in the retinal pigmented epithelium (RPE), a support layer for cones. Our goal was to learn more of TXNIP's structure-function relationships for cone survival, as well as determine the optimal cell type expression pattern for cone survival. The C-terminal half of TXNIP was found to be sufficient to remove GLUT1 from the cell surface, and improved RP cone survival, when expressed in the RPE, but not in cones. Knock-down of HSP90AB1, a TXNIP-interactor which regulates metabolism, improved the survival of cones alone and was additive for cone survival when combined with TXNIP. From these and other results, it is likely that TXNIP interacts with several proteins in the RPE to indirectly support cone survival, with some of these interactions different from those that lead to cone survival when expressed only in cones.

Asunto(s)

Células Fotorreceptoras Retinianas Conos , Retinitis Pigmentosa , Tiorredoxinas , Animales , Ratones , Alelos , Proteínas Portadoras/genética , Proteínas Portadoras/metabolismo , Supervivencia Celular , Modelos Animales de Enfermedad , Eliminación de Gen , Mutación Missense , Células Fotorreceptoras Retinianas Conos/metabolismo , Células Fotorreceptoras Retinianas Conos/patología , Epitelio Pigmentado de la Retina/metabolismo , Retinitis Pigmentosa/genética , Retinitis Pigmentosa/metabolismo , Tiorredoxinas/genética , Tiorredoxinas/metabolismo

RESUMEN

While dysfunction and death of light-detecting photoreceptor cells underlie most inherited retinal dystrophies, knowledge of the species-specific details of human rod and cone photoreceptor cell development remains limited. Here, we generated retinal organoids carrying retinal disease-causing variants in NR2E3, as well as isogenic and unrelated controls. Organoids were sampled using single-cell RNA sequencing (scRNA-Seq) across the developmental window encompassing photoreceptor specification, emergence, and maturation. Using scRNA-Seq data, we reconstruct the rod photoreceptor developmental lineage and identify a branch point unique to the disease state. We show that the rod-specific transcription factor NR2E3 is required for the proper expression of genes involved in phototransduction, including rhodopsin, which is absent in divergent rods. NR2E3-null rods additionally misexpress several cone-specific phototransduction genes. Using joint multimodal single-cell sequencing, we further identify putative regulatory sites where rod-specific factors act to steer photoreceptor cell development. Finally, we show that rod-committed photoreceptor cells form and persist throughout life in a patient with NR2E3-associated disease. Importantly, these findings are strikingly different from those observed in Nr2e3 rodent models. Together, these data provide a road map of human photoreceptor development and leverage patient induced pluripotent stem cells to define the specific roles of rod transcription factors in photoreceptor cell emergence and maturation in health and disease.

Asunto(s)

Organoides , Receptores Nucleares Huérfanos , Células Fotorreceptoras Retinianas Bastones , Humanos , Organoides/metabolismo , Organoides/patología , Células Fotorreceptoras Retinianas Bastones/metabolismo , Células Fotorreceptoras Retinianas Bastones/patología , Receptores Nucleares Huérfanos/genética , Receptores Nucleares Huérfanos/metabolismo , Células Fotorreceptoras Retinianas Conos/metabolismo , Células Fotorreceptoras Retinianas Conos/patología , Retina/metabolismo , Retina/patología , Retina/crecimiento & desarrollo , Diferenciación Celular , Fototransducción/genética , Análisis de la Célula Individual

RESUMEN

PURPOSE: To assess the cone photoreceptors' morphology and associated retinal sensitivity in laser-induced retinopathy (LIR) using adaptive optics scanning laser ophthalmoscopy (AO-SLO) and microperimetry (MP). DESIGN: Cohort study. METHODS: This study included 13 patients (15 eyes) with LIR and 38 age-matched healthy volunteers (38 eyes). Participants underwent comprehensive evaluations including AO-SLO, MP, and spectral-domain OCT. Lesion morphology, cone density, dispersion, and regularity in AO-SLO were assessed and correlated with visual function. RESULTS: In AO-SLO images, LIR lesions were predominantly characterized by hyporeflective regions, suggesting potential cone loss at the fovea, accompanied by the presence of sizable clumps of hyperreflective material within these lesions. The average size of lesions in affected eyes was 97,128±107,478 µm², ranging from 6705 to 673,348 µm². Compared with the healthy contralateral eye and control group, LIR demonstrated significantly reduced cone density, increased cone dispersion, and notably decreased cone regularity in all 4 quadrants at 3° eccentricity (all P values < .05). Lesion morphology in AO-SLO correlated with ellipsoid zone defects observed in OCT, showing a positive correlation in size (r = 0.84, P < .001) but not with retinal sensitivities (P = .09). Similarly, cone density at 3° eccentricity did not correlate with retinal sensitivities (P = .13). CONCLUSIONS AND RELEVANCE: The study provides crucial insights into the morphologic and functional impacts of LIR on cone photoreceptors, revealing significant morphologic changes in cones that do not consistently align with functional outcomes. This research highlights the need for continued exploration into the relationship between retinal structure and function in LIR, and the importance of heightened public awareness and preventive strategies to mitigate the risk of LIR.

Asunto(s)

Oftalmoscopía , Células Fotorreceptoras Retinianas Conos , Enfermedades de la Retina , Tomografía de Coherencia Óptica , Agudeza Visual , Pruebas del Campo Visual , Campos Visuales , Humanos , Masculino , Femenino , Tomografía de Coherencia Óptica/métodos , Células Fotorreceptoras Retinianas Conos/patología , Células Fotorreceptoras Retinianas Conos/fisiología , Agudeza Visual/fisiología , Campos Visuales/fisiología , Adulto , Persona de Mediana Edad , Enfermedades de la Retina/fisiopatología , Enfermedades de la Retina/diagnóstico , Enfermedades de la Retina/etiología , Recuento de Células , Anciano

RESUMEN

Age-related macular degeneration (AMD) is the most common cause of untreatable blindness in the developed world. Recently, CDHR1 has been identified as the cause of a subset of AMD that has the appearance of the "dry" form, or geographic atrophy. Biallelic variants in CDHR1-a specialized protocadherin highly expressed in cone and rod photoreceptors-result in blindness from shortened photoreceptor outer segments and progressive photoreceptor cell death. Here we demonstrate long-term morphological, ultrastructural, functional, and behavioral rescue following CDHR1 gene therapy in a relevant murine model, sustained to 23-months after injection. This represents the first demonstration of rescue of a monogenic cadherinopathy in vivo. Moreover, the durability of CDHR1 gene therapy seems to be near complete-with morphological findings of the rescued retina not obviously different from wildtype throughout the lifespan of the mouse model. A follow-on clinical trial in patients with CDHR1-associated retinal degeneration is warranted. Hypomorphic CDHR1 variants may mimic advanced dry AMD. Accurate clinical classification is now critical, as their pathogenesis and treatment are distinct.

Asunto(s)

Proteínas Relacionadas con las Cadherinas , Cadherinas , Modelos Animales de Enfermedad , Terapia Genética , Proteínas del Tejido Nervioso , Células Fotorreceptoras Retinianas Conos , Degeneración Retiniana , Células Fotorreceptoras Retinianas Bastones , Animales , Ratones , Células Fotorreceptoras Retinianas Bastones/metabolismo , Células Fotorreceptoras Retinianas Bastones/patología , Células Fotorreceptoras Retinianas Conos/metabolismo , Células Fotorreceptoras Retinianas Conos/patología , Cadherinas/genética , Cadherinas/metabolismo , Degeneración Retiniana/genética , Degeneración Retiniana/terapia , Degeneración Retiniana/etiología , Humanos , Terapia Genética/métodos , Degeneración Macular/terapia , Degeneración Macular/genética , Degeneración Macular/patología , Degeneración Macular/etiología , Degeneración Macular/metabolismo

RESUMEN

PURPOSE: To investigate the temporal sequence of changes in the photoreceptor cell mosaic in patients with Stargardt disease type 1, using adaptive optics scanning laser ophthalmoscopy. METHODS: Two brothers with genetically confirmed Stargardt disease type 1 underwent comprehensive eye exams, spectral-domain optical coherence tomography, fundus autofluorescence, and adaptive optics scanning laser ophthalmoscopy imaging 3 times over the course of 28 months. Confocal images of the cones and rods were obtained from the central fovea to 10° inferiorly. Photoreceptors were counted in sampling windows at 100- µ m intervals of 200 µ m × 200 µ m for cones and 50 µ m × 50 µ m for rods, using custom cell marking software with manual correction. Photoreceptor density and spacing were measured and compared across imaging sessions using one-way analysis of variance. RESULTS: Adaptive optics scanning laser ophthalmoscopy revealed the younger brother had a 30% decline in foveal cone density after 8 months, followed by complete loss of foveal cones at 28 months; the older brother had no detectable foveal cones at baseline. In the peripheral macula, cone and rod spacings were greater than normal in both patients. The ratio of the cone spacing to rod spacing was greater than normal across all eccentricities, with a greater divergence closer to the foveal center. CONCLUSION: Cone cell loss may be an early pathogenetic step in Stargardt disease. Adaptive optics scanning laser ophthalmoscopy provides the capability to track individual photoreceptor changes longitudinally in Stargardt disease.

Asunto(s)

Degeneración Macular , Oftalmoscopía , Células Fotorreceptoras Retinianas Conos , Células Fotorreceptoras Retinianas Bastones , Enfermedad de Stargardt , Tomografía de Coherencia Óptica , Humanos , Oftalmoscopía/métodos , Células Fotorreceptoras Retinianas Conos/patología , Masculino , Tomografía de Coherencia Óptica/métodos , Células Fotorreceptoras Retinianas Bastones/patología , Degeneración Macular/congénito , Degeneración Macular/diagnóstico , Degeneración Macular/genética , Agudeza Visual , Adulto , Angiografía con Fluoresceína/métodos , Recuento de Células , Adolescente

RESUMEN

PURPOSE: To characterize any differences in the vasculature and cone photoreceptor packing geometry (CPG) between subjects with diabetes without/no diabetic retinopathy (NDR) and healthy controls. METHODS: Eight NDR and five controls were enrolled. Optical coherence tomography angiography (OCTA) taken at the macula was used to measure vessel density, vessel length density, and vessel density index (VDI) in three vascular plexuses, namely, the superficial vascular plexus, intermediate capillary plexus, and deep capillary plexus (DCP). The choriocapillaris (CC) flow deficit (FD) was also measured. OCTA images were binarized and processed to extrapolate the parafovea and parafoveal quadrants and the OCTA indices mentioned above. The CC was processed with six different radii to quantify FD. Adaptive optics - scanning laser ophthalmoscopy images were acquired and processed to extract CPG indices, i.e., cone density (CD), cone-to-cone spacing (CS), linear dispersion index, heterogeneity packing index and percent of cells with six neighbors at 3.6° in the temporal retina. RESULTS: In all eyes, statistically significant differences were found (i) in parafoveal FD across the six radii (p < 0.001) and (ii) in the correlation between the parafoveal temporal quadrant (PTQ) DCP VDI and CS (r = 0.606, p = 0.048). No other significant correlations were found. For OCTA or CPG indices, no significant differences were found between the cohorts in the parafovea or parafoveal quadrants. CONCLUSIONS: CS is the most sensitive CPG index for detecting alterations in the cone mosaic. The DCP and the cone photoreceptors are significantly correlated, indicating that alterations in the DCP can affect the cones. Future work elucidating the vascular alterations and neurodegeneration present in diabetic eyes should focus on the DCP and multiple CPG indices, not solely CD. Moreover, such alterations are highly localized, hence using larger regions e.g. parafovea versus smaller areas, such as the PTQ, will potentially mask significant correlations.

Asunto(s)

Retinopatía Diabética , Angiografía con Fluoresceína , Células Fotorreceptoras Retinianas Conos , Vasos Retinianos , Tomografía de Coherencia Óptica , Humanos , Tomografía de Coherencia Óptica/métodos , Células Fotorreceptoras Retinianas Conos/patología , Masculino , Femenino , Vasos Retinianos/diagnóstico por imagen , Vasos Retinianos/patología , Vasos Retinianos/fisiopatología , Persona de Mediana Edad , Retinopatía Diabética/fisiopatología , Retinopatía Diabética/diagnóstico , Angiografía con Fluoresceína/métodos , Oftalmoscopía , Anciano , Fondo de Ojo , Adulto , Agudeza Visual/fisiología , Mácula Lútea/patología

RESUMEN

BACKGROUND: ATF6-associated Achromatopsia (ACHM) is a rare autosomal recessive disorder characterized by reduction of visual acuity, photophobia, nystagmus, and poor color vision. METHODS: Detailed ophthalmological examinations were performed in a Chinese patient with ACHM. Whole exome sequencing and Sanger sequencing were performed to detect the disease-causing gene in the patient. RESULTS: A 6-year-old girl presented photophobia, low vision and reduced color discrimination. Small yellow lesion in the macula of both eyes was observed. FAF demonstrated hypofluorescence in the macular fovea. OCT images revealed interruption of ellipsoid and interdigitation zone in the foveal area and a loss of the foveal pit. ERG showed relatively normal rod responses and unrecordable cone responses. Sequencing result identified a novel splicing variant c.354 + 6T>C in the ATF6 gene (NM_007348.4). CONCLUSIONS: We reported detailed clinical features and genetic analysis of a new Chinese ATF6-associated patient with ACHM.

Asunto(s)

Defectos de la Visión Cromática , Niño , Femenino , Humanos , Factor de Transcripción Activador 6/genética , China , Defectos de la Visión Cromática/diagnóstico , Fotofobia/diagnóstico , Fotofobia/patología , Células Fotorreceptoras Retinianas Conos/patología , Tomografía de Coherencia Óptica/métodos

RESUMEN

PURPOSE: Progressive inherited retinal degenerations (IRDs) affecting rods and cones are clinically and genetically heterogeneous and can lead to blindness with limited therapeutic options. The major gene defects have been identified in subjects of European and Asian descent with only few reports of North African descent. METHODS: Genome, targeted next-generation, and Sanger sequencing was applied to cohort of ∼4000 IRDs cases. Expression analyses were performed including Chip-seq database analyses, on human-derived retinal organoids (ROs), retinal pigment epithelium cells, and zebrafish. Variants' pathogenicity was accessed using 3D-modeling and/or ROs. RESULTS: Here, we identified a novel gene defect with three distinct pathogenic variants in UBAP1L in 4 independent autosomal recessive IRD cases from Tunisia. UBAP1L is expressed in the retinal pigment epithelium and retina, specifically in rods and cones, in line with the phenotype. It encodes Ubiquitin-associated protein 1-like, containing a solenoid of overlapping ubiquitin-associated domain, predicted to interact with ubiquitin. In silico and in vitro studies, including 3D-modeling and ROs revealed that the solenoid of overlapping ubiquitin-associated domain is truncated and thus ubiquitin binding most likely abolished secondary to all variants identified herein. CONCLUSION: Biallelic UBAP1L variants are a novel cause of IRDs, most likely enriched in the North African population.

Asunto(s)

Distrofias de Conos y Bastones , Linaje , Pez Cebra , Humanos , Distrofias de Conos y Bastones/genética , Distrofias de Conos y Bastones/patología , Masculino , Femenino , Pez Cebra/genética , Animales , Genes Recesivos , Epitelio Pigmentado de la Retina/metabolismo , Epitelio Pigmentado de la Retina/patología , Mutación/genética , Células Fotorreceptoras Retinianas Conos/patología , Células Fotorreceptoras Retinianas Conos/metabolismo , Retina/patología , Retina/metabolismo , Adulto , Túnez , Retinitis Pigmentosa/genética , Retinitis Pigmentosa/patología , Fenotipo , Células Fotorreceptoras Retinianas Bastones/metabolismo , Células Fotorreceptoras Retinianas Bastones/patología

RESUMEN

Purpose: Canine models of inherited retinal degeneration are used for proof of concept of emerging gene and cell-based therapies that aim to produce functional restoration of cone-mediated vision. We examined functional magnetic resonance imaging (MRI) measures of the postretinal response to cone-directed stimulation in wild-type (WT) dogs, and in three different retinal disease models. Methods: Temporal spectral modulation of a uniform field of light around a photopic background was used to target the canine L/M (hereafter "L") and S cones and rods. Stimuli were designed to separately target the postreceptoral luminance (L+S) and chrominance (L-S) pathways, the rods, and all photoreceptors jointly (light flux). These stimuli were presented to WT, and mutant PDE6B-RCD1, RPGR-XLPRA2, and NPHP5-CRD2 dogs during pupillometry and functional MRI (fMRI). Results: Pupil responses in WT dogs to light flux, L+S, and rod-directed stimuli were consistent with responses being driven by cone signals alone. For WT animals, both luminance and chromatic (L-S) stimuli evoked fMRI responses in the lateral geniculate nucleus or visual cortex; RCD1 animals with predominant rod loss had similar responses. Responses to cone-directed stimulation were reduced in XLPRA2 and absent in CRD2. NPHP5 gene augmentation restored the cortical response to luminance stimulation in a CRD2 animal. Conclusions: Cone-directed stimulation during fMRI can be used to measure the integrity of luminance and chrominance responses in the dog visual system. The NPHP5-CRD2 model is appealing for studies of recovered cone function. Translational Relevance: fMRI assessment of cone-driven cortical response provides a tool to translate cell/gene therapies for vision restoration.

Asunto(s)

Degeneración Retiniana , Células Fotorreceptoras Retinianas Bastones , Perros , Animales , Células Fotorreceptoras Retinianas Bastones/patología , Células Fotorreceptoras Retinianas Bastones/fisiología , Células Fotorreceptoras Retinianas Conos/metabolismo , Células Fotorreceptoras Retinianas Conos/patología , Retina/diagnóstico por imagen , Visión Ocular , Degeneración Retiniana/patología