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Holden JM, Wareham LK, Calkins DJ. Morphological and electrophysiological characterization of a novel displaced astrocyte in the mouse retina. Glia 2024; 72:1356-1370. [PMID: 38591270 PMCID: PMC11081821 DOI: 10.1002/glia.24536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2023] [Revised: 03/08/2024] [Accepted: 03/30/2024] [Indexed: 04/10/2024]
Abstract
Astrocytes throughout the central nervous system are heterogeneous in both structure and function. This diversity leads to tissue-specific specialization where morphology is adapted to the surrounding neuronal circuitry, as seen in Bergman glia of the cerebellum and Müller glia of the retina. Because morphology can be a differentiating factor for cellular classification, we recently developed a mouse where glial-fibrillary acidic protein (GFAP)-expressing cells stochastically label for full membranous morphology. Here we utilize this tool to investigate whether morphological and electrophysiological features separate types of mouse retinal astrocytes. In this work, we report on a novel glial population found in the inner plexiform layer and ganglion cell layer which expresses the canonical astrocyte markers GFAP, S100β, connexin-43, Sox2 and Sox9. Apart from their retinal layer localization, these cells are unique in their radial distribution. They are notably absent from the mid-retina but are heavily concentrated near the optic nerve head, and to a lesser degree the peripheral retina. Additionally, their morphology is distinct from both nerve fiber layer astrocytes and Müller glia, appearing more similar to amacrine cells. Despite this structural similarity, these cells lack protein expression of common neuronal markers. Additionally, they do not exhibit action potentials, but rather resemble astrocytes and Müller glia in their small amplitude, graded depolarization to both light onset and offset. Their structure, protein expression, physiology, and intercellular connections suggest that these cells are astrocytic, displaced from their counterparts in the nerve fiber layer. As such, we refer to these cells as displaced retinal astrocytes.
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Affiliation(s)
- Joseph Matthew Holden
- Department of Ophthalmology and Visual Sciences, Vanderbilt University Medical Center, Nashville, TN 37212
- Vanderbilt Neuroscience Graduate Program, Vanderbilt University, Nashville, TN 37212
| | - Lauren Katie Wareham
- Department of Ophthalmology and Visual Sciences, Vanderbilt University Medical Center, Nashville, TN 37212
| | - David John Calkins
- Department of Ophthalmology and Visual Sciences, Vanderbilt University Medical Center, Nashville, TN 37212
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Zhang X, Wang X, Wang S, Peng W, Ullah R, Fu J, Zhou Y, Shen Y. Trilogy Development of Proopiomelanocortin Neurons From Embryonic to Adult Stages in the Mice Retina. Front Cell Dev Biol 2021; 9:718851. [PMID: 34676208 PMCID: PMC8523858 DOI: 10.3389/fcell.2021.718851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 09/06/2021] [Indexed: 11/13/2022] Open
Abstract
Proopiomelanocortin-positive amacrine cells (POMC ACs) were first discovered in adult mouse retinas in 2010; however, the development of POMC-ACs has not been studied. We bred POMC-EGFP mice to label POMC-positive cells and investigated the development of POMC neurons from embryonic to adult stages. We found that POMC neuron development is mainly divided into three stages: the embryonic stage, the closed-eye stage, and the open-eye stage. Each stage has unique characteristics. In the embryonic stage, POMC neurons appeared in the retina at about E13. There was a cell number developmental peak at E15, followed by a steep decline at E16. POMC neurons showed a large soma and increased spine numbers at the closed-eye stage, and two dendritic sublaminas formed in the inner plexiform layer (IPL). The appearance and increased soma size and dendrite numbers did not occur continuously in space. We found that the soma number was asymmetric between the superior and inferior retinas according to the developmental topographic map. Density peaked in the superior retina, which existed persistently in the retinal ganglion cell layer (GCL), but disappeared from the inner nuclear layer (INL) at about P6. At the same time, the soma distribution in the INL was the most regular. At the open-eye stage, the development of POMC neurons was nearly stable only with only an increase in the IPL width, which increased the soma–dendrite distance.
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Affiliation(s)
- Xuhong Zhang
- Department of Ophthalmology, The First Affiliated Hospital of Zhejiang University, Hangzhou, China
| | - Xiaoyu Wang
- Department of Ophthalmology, The First Affiliated Hospital of Zhejiang University, Hangzhou, China.,Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, China
| | - Senjie Wang
- Department of Endocrinology, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Wei Peng
- Department of Endocrinology, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Rahim Ullah
- Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, China.,Department of Endocrinology, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Junfen Fu
- Department of Endocrinology, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yudong Zhou
- Department of Ophthalmology, The First Affiliated Hospital of Zhejiang University, Hangzhou, China.,Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, China
| | - Ye Shen
- Department of Ophthalmology, The First Affiliated Hospital of Zhejiang University, Hangzhou, China
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Rochon PL, Theriault C, Rangel Olguin AG, Krishnaswamy A. The cell adhesion molecule Sdk1 shapes assembly of a retinal circuit that detects localized edges. eLife 2021; 10:e70870. [PMID: 34545809 PMCID: PMC8514235 DOI: 10.7554/elife.70870] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 09/11/2021] [Indexed: 01/10/2023] Open
Abstract
Nearly 50 different mouse retinal ganglion cell (RGC) types sample the visual scene for distinct features. RGC feature selectivity arises from their synapses with a specific subset of amacrine (AC) and bipolar cell (BC) types, but how RGC dendrites arborize and collect input from these specific subsets remains poorly understood. Here we examine the hypothesis that RGCs employ molecular recognition systems to meet this challenge. By combining calcium imaging and type-specific histological stains, we define a family of circuits that express the recognition molecule Sidekick-1 (Sdk1), which include a novel RGC type (S1-RGC) that responds to local edges. Genetic and physiological studies revealed that Sdk1 loss selectively disrupts S1-RGC visual responses, which result from a loss of excitatory and inhibitory inputs and selective dendritic deficits on this neuron. We conclude that Sdk1 shapes dendrite growth and wiring to help S1-RGCs become feature selective.
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