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Investigative Ophthalmology & Visual... Jul 2021Primary cilia are conserved organelles found in polarized cells within the eye that regulate cell growth, migration, and differentiation. Although the role of cilia in...
PURPOSE
Primary cilia are conserved organelles found in polarized cells within the eye that regulate cell growth, migration, and differentiation. Although the role of cilia in photoreceptors is well-studied, the formation of cilia in other retinal cell types has received little attention. In this study, we examined the ciliary profile focused on the inner nuclear layer of retinas in mice and rhesus macaque primates.
METHODS
Retinal sections or flatmounts from Arl13b-Cetn2 tg transgenic mice were immunostained for cell markers (Pax6, Sox9, Chx10, Calbindin, Calretinin, ChaT, GAD67, Prox1, TH, and vGluT3) and analyzed by confocal microscopy. Primate retinal sections were immunostained for ciliary and cell markers (Pax6 and Arl13b). Optical coherence tomography (OCT) and ERGs were used to assess visual function of Vift88 mice.
RESULTS
During different stages of mouse postnatal eye development, we found that cilia are present in Pax6-positive amacrine cells, which were also observed in primate retinas. The cilia of subtypes of amacrine cells in mice were shown by immunostaining and electron microscopy. We also removed primary cilia from vGluT3 amacrine cells in mouse and found no significant vision defects. In addition, cilia were present in the outer limiting membrane, suggesting that a population of Müller glial cells forms cilia.
CONCLUSIONS
We report that several subpopulations of amacrine cells in inner nuclear layers of the retina form cilia during early retinal development in mice and primates.
Topics: Amacrine Cells; Animals; Chickens; Cilia; Electroretinography; Mice; Mice, Inbred C57BL; Mice, Transgenic; Microscopy, Electron; Models, Animal; Rabbits; Retina; Tomography, Optical Coherence
PubMed: 34241625
DOI: 10.1167/iovs.62.9.15 -
ELife Aug 2015Proteins called gamma-protocadherins are essential for the establishment of working circuits of neurons in the retina.
Proteins called gamma-protocadherins are essential for the establishment of working circuits of neurons in the retina.
Topics: Amacrine Cells; Animals; Cadherins; Dendrites
PubMed: 26305501
DOI: 10.7554/eLife.10233 -
The Journal of Neuroscience : the... Jul 2014The retina contains two populations of cholinergic amacrine cells, one positioned in the ganglion cell layer (GCL) and the other in the inner nuclear layer (INL), that...
The retina contains two populations of cholinergic amacrine cells, one positioned in the ganglion cell layer (GCL) and the other in the inner nuclear layer (INL), that together comprise ∼1/2 of a percent of all retinal neurons. The present study examined the genetic control of cholinergic amacrine cell number and distribution between these two layers. The total number of cholinergic amacrine cells was quantified in the C57BL/6J and A/J inbred mouse strains, and in 25 recombinant inbred strains derived from them, and variations in their number and ratio (GCL/INL) across these strains were mapped to genomic loci. The total cholinergic amacrine cell number was found to vary across the strains, from 27,000 to 40,000 cells, despite little variation within individual strains. The number of cells was always lower within the GCL relative to the INL, and the sizes of the two populations were strongly correlated, yet there was variation in their ratio between the strains. Approximately 1/3 of that variation in cell ratio was mapped to a locus on chromosome 3, where Sex determining region Y box 2 (Sox2) was identified as a candidate gene due to the presence of a 6-nucleotide insertion in the protein-coding sequence in C57BL/6J and because of robust and selective expression in cholinergic amacrine cells. Conditionally deleting Sox2 from the population of nascent cholinergic amacrine cells perturbed the normal ratio of cells situated in the GCL versus the INL and induced a bistratifying morphology, with dendrites distributed to both ON and OFF strata within the inner plexiform layer.
Topics: Amacrine Cells; Animals; Cell Count; Cells, Cultured; Cholinergic Neurons; Dendrites; Female; Male; Mice; Mice, 129 Strain; Mice, Inbred A; Mice, Inbred C57BL; Mice, Knockout; Mice, Transgenic; Retina; SOXB1 Transcription Factors
PubMed: 25057212
DOI: 10.1523/JNEUROSCI.0415-14.2014 -
Cell Reports Feb 2022In the retina, ON starburst amacrine cells (SACs) play a crucial role in the direction-selective circuit, but the sources of inhibition that shape their response...
In the retina, ON starburst amacrine cells (SACs) play a crucial role in the direction-selective circuit, but the sources of inhibition that shape their response properties remain unclear. Previous studies demonstrate that ∼95% of their inhibitory synapses are GABAergic, yet we find that the light-evoked inhibitory currents measured in SACs are predominantly glycinergic. Glycinergic inhibition is extremely slow, relying on non-canonical glycine receptors containing α4 subunits, and is driven by both the ON and OFF retinal pathways. These attributes enable glycine inputs to summate and effectively control the output gain of SACs, expanding the range over which they compute direction. Serial electron microscopic reconstructions reveal three specific types of ON and OFF narrow-field amacrine cells as the presumptive sources of glycinergic inhibition. Together, these results establish an unexpected role for specific glycinergic amacrine cells in the retinal computation of stimulus direction by SACs.
Topics: Amacrine Cells; Glycine; Retina; Synapses
PubMed: 35196487
DOI: 10.1016/j.celrep.2022.110410 -
Experimental Eye Research Jun 2024Aging is a major risk factor for the development or the worsening of retinal degenerative conditions. The intricate network of the neural retina determined that the...
Aging is a major risk factor for the development or the worsening of retinal degenerative conditions. The intricate network of the neural retina determined that the retinal aging is a complicated process. The aim of this study is to delineate the transcriptomic changes of major retinal neurons during aging in C57BL/6 mice at single-cell level. We analyzed the transcriptional profiles of the photoreceptor, bipolar, amacrine, and Müller glial cells of 1.5-2 and 24-30 months old mice using single-cell RNA sequencing technique. We selectively confirmed the differences in gene expression using immunofluorescence staining and RNA in situ hybridization analysis. We found that each retinal cell type had unique changes upon aging. However, they all showed signs of dysregulated glucose and energy metabolism, and perturbed proteostasis. In particular, old Müller glia exhibited the most profound changes, including the upregulation of cell metabolism, stress-responses, antigen-presentation and immune responses and metal ion homeostasis. The dysregulated gliogenesis and differentiation was confirmed by the presence of Müller glia expressing rod-specific genes in the inner nuclear layer and the outer plexiform layer of the old retina. We further pinpointed the specific loss of GABAergic amacrine cells in old retina. Our study emphasized changes of amacrine and Müller glia during retinal aging, provided resources for further research on the molecular and cellular regulatory mechanisms underlying aging-associated retinal deterioration.
PubMed: 38945518
DOI: 10.1016/j.exer.2024.109985 -
Frontiers in Cellular Neuroscience 2021A presynaptic neuron can increase its computational capacity by transmitting functionally distinct signals to each of its postsynaptic cell types. To determine whether...
A presynaptic neuron can increase its computational capacity by transmitting functionally distinct signals to each of its postsynaptic cell types. To determine whether such computational specialization occurs over fine spatial scales within a neurite arbor, we investigated computation at output synapses of the starburst amacrine cell (SAC), a critical component of the classical direction-selective (DS) circuit in the retina. The SAC is a non-spiking interneuron that co-releases GABA and acetylcholine and forms closely spaced (<5 μm) inhibitory synapses onto two postsynaptic cell types: DS ganglion cells (DSGCs) and neighboring SACs. During dynamic optogenetic stimulation of SACs in mouse retina, whole-cell recordings of inhibitory postsynaptic currents revealed that GABAergic synapses onto DSGCs exhibit stronger low-pass filtering than those onto neighboring SACs. Computational analyses suggest that this filtering difference can be explained primarily by presynaptic properties, rather than those of the postsynaptic cells . Consistent with functionally diverse SAC presynapses, blockade of N-type voltage-gated calcium channels abolished GABAergic currents in SACs but only moderately reduced GABAergic and cholinergic currents in DSGCs. These results jointly demonstrate how specialization of synaptic outputs could enhance parallel processing in a compact interneuron over fine spatial scales. Moreover, the distinct transmission kinetics of GABAergic SAC synapses are poised to support the functional diversity of inhibition within DS circuitry.
PubMed: 34381333
DOI: 10.3389/fncel.2021.660773 -
ELife Nov 2018Retinal dopamine is a critical modulator of high acuity, light-adapted vision and photoreceptor coupling in the retina. Dopaminergic amacrine cells (DACs) serve as the...
Retinal dopamine is a critical modulator of high acuity, light-adapted vision and photoreceptor coupling in the retina. Dopaminergic amacrine cells (DACs) serve as the sole source of retinal dopamine, and dopamine release in the retina follows a circadian rhythm and is modulated by light exposure. However, the retinal circuits through which light influences the development and function of DACs are still unknown. Intrinsically photosensitive retinal ganglion cells (ipRGCs) have emerged as a prime target for influencing retinal dopamine levels because they costratify with DACs in the inner plexiform layer and signal to them in a retrograde manner. Surprisingly, using genetic mouse models lacking specific phototransduction pathways, we find that while light influences the total number of DACs and retinal dopamine levels, this effect does not require ipRGCs. Instead, we find that the rod pathway is a critical modulator of both DAC number and retinal dopamine levels.
Topics: Amacrine Cells; Animals; Cell Count; Dopamine; Female; Light; Light Signal Transduction; Male; Mice; Models, Biological; Retinal Cone Photoreceptor Cells; Retinal Ganglion Cells; Retinal Rod Photoreceptor Cells; Rod Opsins; Tyrosine 3-Monooxygenase
PubMed: 30403373
DOI: 10.7554/eLife.39866 -
Nature Communications May 2022From mouse to primate, there is a striking discontinuity in our current understanding of the neural coding of motion direction. In non-primate mammals, directionally...
From mouse to primate, there is a striking discontinuity in our current understanding of the neural coding of motion direction. In non-primate mammals, directionally selective cell types and circuits are a signature feature of the retina, situated at the earliest stage of the visual process. In primates, by contrast, direction selectivity is a hallmark of motion processing areas in visual cortex, but has not been found in the retina, despite significant effort. Here we combined functional recordings of light-evoked responses and connectomic reconstruction to identify diverse direction-selective cell types in the macaque monkey retina with distinctive physiological properties and synaptic motifs. This circuitry includes an ON-OFF ganglion cell type, a spiking, ON-OFF polyaxonal amacrine cell and the starburst amacrine cell, all of which show direction selectivity. Moreover, we discovered that macaque starburst cells possess a strong, non-GABAergic, antagonistic surround mediated by input from excitatory bipolar cells that is critical for the generation of radial motion sensitivity in these cells. Our findings open a door to investigation of a precortical circuitry that computes motion direction in the primate visual system.
Topics: Amacrine Cells; Animals; Connectome; Evoked Potentials, Visual; Macaca; Mammals; Mice; Primates; Retina; Retinal Ganglion Cells; Synapses
PubMed: 35606344
DOI: 10.1038/s41467-022-30405-5 -
Methods in Molecular Biology (Clifton,... 2023Electroretinography allows for noninvasive functional assessment of the retina and is a mainstay for preclinical studies of retinal function in health and disease. The...
Electroretinography allows for noninvasive functional assessment of the retina and is a mainstay for preclinical studies of retinal function in health and disease. The full-field electroretinogram is useful for a variety of applications as it returns a functional readout from each of the major cell classes within the retina: photoreceptors, bipolar cells, amacrine cells, and retinal ganglion cells. Rodent models are commonly employed in ocular degeneration studies due to the fast throughput of these mammalian species and the conservation of the electroretinogram from the preclinic to the clinic. Here we describe approaches for in vivo electroretinography in rodent models.
Topics: Animals; Electroretinography; Rodentia; Retina; Retinal Ganglion Cells; Amacrine Cells
PubMed: 37558967
DOI: 10.1007/978-1-0716-3409-7_14 -
Frontiers in Bioscience (Landmark... May 2023Neurodegenerative diseases, such as diabetic retinopathy (DR) and glaucoma, induce retinal neuron loss. Acetylcholine-containing cholinergic neurons, known as starburst...
BACKGROUND
Neurodegenerative diseases, such as diabetic retinopathy (DR) and glaucoma, induce retinal neuron loss. Acetylcholine-containing cholinergic neurons, known as starburst amacrine cells (SACs), play critical roles in the generation of precise neuronal activity in the retina and are located in the inner nuclear layer (INL, conventional) and ganglion cell layer (GCL, displaced).
METHODS
This study investigated the loss of and morphological changes in SACs in the retinas of streptozotocin (STZ)-induced diabetic and insulin-deficient C57BL/6-Tg(pH1-siRNAinsulin/CMV-hIDE)/Korl (IDCK) mice. SACs were immunocytochemically localized with anti-choline acetyltransferase (ChAT) antibody, and ChAT-labeled cells in the INL and GCL in the control and experimental groups were counted along the central vertical meridian in the whole-mounted retina using conventional fluorescent or confocal microscopes.
RESULTS
ChAT-immunoreactive (IR) neurons in STZ-induced diabetic mouse retina decreased by 8.34% at 4-6 weeks and by 14.89% at 42 weeks compared with the control group. Localized ChAT-IR neuron counts in the retinas of 20-week-old IDCK mice were 16.80% lower than those of age-matched control mice. Cell body deformation and aggregation were detected in the retinas of mice with DR. Single-cell injection experiments revealed the loss and deformation of dendritic branches in ChAT-IR neurons in DR. All ChAT-IR neurons expressed the calcium-binding protein calretinin, whereas no ChAT-IR neuron colocalized with calbindin-D28K or parvalbumin.
CONCLUSIONS
Our results revealed that the neurodegenerative effects of the loss and deformation of ChAT-IR neurons can provide a reference for future study of this disease.
Topics: Mice; Animals; Amacrine Cells; Diabetic Retinopathy; Mice, Inbred C57BL; Retina; Calcium-Binding Proteins; Diabetes Mellitus
PubMed: 37258479
DOI: 10.31083/j.fbl2805092