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Zegeye Y, Aredo B, Yuksel S, Kirman DC, Kumar A, Chen B, Turpin E, Shresta S, He YG, Gautron L, Tang M, Li X, DiCesare SM, Hulleman JD, Xing C, Ludwig S, Moresco EMY, Beutler BA, Ufret-Vincenty RL. E3 ubiquitin ligase Herc3 deficiency leads to accumulation of subretinal microglia and retinal neurodegeneration. Sci Rep 2024; 14:3010. [PMID: 38321224 PMCID: PMC10847449 DOI: 10.1038/s41598-024-53731-8] [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: 08/01/2023] [Accepted: 02/04/2024] [Indexed: 02/08/2024] Open
Abstract
Activated microglia have been implicated in the pathogenesis of age-related macular degeneration (AMD), diabetic retinopathy, and other neurodegenerative and neuroinflammatory disorders, but our understanding of the mechanisms behind their activation is in infant stages. With the goal of identifying novel genes associated with microglial activation in the retina, we applied a semiquantitative fundus spot scoring scale to an unbiased, state-of-the-science mouse forward genetics pipeline. A mutation in the gene encoding the E3 ubiquitin ligase Herc3 led to prominent accumulation of fundus spots. CRISPR mutagenesis was used to generate Herc3-/- mice, which developed prominent accumulation of fundus spots and corresponding activated Iba1 + /CD16 + subretinal microglia, retinal thinning on OCT and histology, and functional deficits by Optomotory and electrophysiology. Bulk RNA sequencing identified activation of inflammatory pathways and differentially expressed genes involved in the modulation of microglial activation. Thus, despite the known expression of multiple E3 ubiquitin ligases in the retina, we identified a non-redundant role for Herc3 in retinal homeostasis. Our findings are significant given that a dysregulated ubiquitin-proteasome system (UPS) is important in prevalent retinal diseases, in which activated microglia appear to play a role. This association between Herc3 deficiency, retinal microglial activation and retinal degeneration merits further study.
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Affiliation(s)
- Yeshumenesh Zegeye
- Department of Ophthalmology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Bogale Aredo
- Department of Ophthalmology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Seher Yuksel
- Department of Ophthalmology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Dogan Can Kirman
- Department of Ophthalmology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Ashwani Kumar
- McDermott Center for Human Growth and Development, UT Southwestern Medical Center, Dallas, TX, USA
| | - Bo Chen
- Department of Ophthalmology, UT Southwestern Medical Center, Dallas, TX, USA
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Emily Turpin
- Department of Ophthalmology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Sangita Shresta
- Department of Ophthalmology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Yu-Guang He
- Department of Ophthalmology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Laurent Gautron
- Center for Hypothalamic Research and Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Miao Tang
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Xiaohong Li
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Sophia M DiCesare
- Department of Ophthalmology, UT Southwestern Medical Center, Dallas, TX, USA
| | - John D Hulleman
- Department of Ophthalmology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Chao Xing
- McDermott Center for Human Growth and Development, UT Southwestern Medical Center, Dallas, TX, USA
- Department of Bioinformatics, UT Southwestern Medical Center, Dallas, TX, USA
| | - Sara Ludwig
- Center for Hypothalamic Research and Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Eva Marie Y Moresco
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Bruce A Beutler
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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Zhu Y, Wang R, Pappas AC, Seifert P, Savol A, Sadreyev RI, Sun D, Jakobs TC. Astrocytes in the Optic Nerve Are Heterogeneous in Their Reactivity to Glaucomatous Injury. Cells 2023; 12:2131. [PMID: 37681863 PMCID: PMC10486930 DOI: 10.3390/cells12172131] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 07/14/2023] [Accepted: 08/18/2023] [Indexed: 09/09/2023] Open
Abstract
The optic nerve head is thought to be the site of initial injury to retinal ganglion cell injury in glaucoma. In the initial segment of the optic nerve directly behind the globe, the ganglion cell axons are unmyelinated and come into direct contact to astrocytes, suggesting that astrocytes may play a role in the pathology of glaucoma. As in other parts of the CNS, optic nerve head astrocytes respond to injury by characteristic changes in cell morphology and gene expression profile. Using RNA-sequencing of glaucomatous optic nerve heads, single-cell PCR, and an in-vivo assay, we demonstrate that an up-regulation of astrocytic phagocytosis is an early event after the onset of increased intraocular pressure. We also show that astrocytes in the glial lamina of the optic nerve are apparently functionally heterogeneous. At any time, even in naïve nerves, some of the cells show signs of reactivity-process hypertrophy, high phagocytic activity, and expression of genetic markers of reactivity whereas neighboring cells apparently are inactive. A period of increased intraocular pressure moves more astrocytes towards the reactive phenotype; however, some cells remain unreactive even in glaucomatous nerves.
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Affiliation(s)
- Ying Zhu
- Department of Ophthalmology, Massachusetts Eye and Ear Infirmary/Schepens Eye Research Institute, Harvard Medical School, 20 Staniford Street, Boston, MA 02114, USA
- Department of Ophthalmology, Stanford University, 1651 Page Mill Road, Palo Alto, CA 94304, USA
| | - Rui Wang
- Department of Ophthalmology, Massachusetts Eye and Ear Infirmary/Schepens Eye Research Institute, Harvard Medical School, 20 Staniford Street, Boston, MA 02114, USA
- Department of Ophthalmology, The First Affiliated Hospital of Northwest University, Xi’an 710002, China
| | - Anthony C. Pappas
- Department of Ophthalmology, Massachusetts Eye and Ear Infirmary/Schepens Eye Research Institute, Harvard Medical School, 20 Staniford Street, Boston, MA 02114, USA
| | - Philip Seifert
- Department of Ophthalmology, Massachusetts Eye and Ear Infirmary/Schepens Eye Research Institute, Harvard Medical School, 20 Staniford Street, Boston, MA 02114, USA
| | - Andrej Savol
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA
- Department of Pathology, Massachusetts General Hospital and Harvard Medical School, 185 Cambridge St., Boston, MA 02114, USA
| | - Ruslan I. Sadreyev
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA
- Department of Pathology, Massachusetts General Hospital and Harvard Medical School, 185 Cambridge St., Boston, MA 02114, USA
| | - Daniel Sun
- Department of Ophthalmology, Massachusetts Eye and Ear Infirmary/Schepens Eye Research Institute, Harvard Medical School, 20 Staniford Street, Boston, MA 02114, USA
| | - Tatjana C. Jakobs
- Department of Ophthalmology, Massachusetts Eye and Ear Infirmary/Schepens Eye Research Institute, Harvard Medical School, 20 Staniford Street, Boston, MA 02114, USA
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Hu B, Huang Y, Jakobs TC, Kang Q, Lv Z, Liu W, Wang R. Viability of mitochondria-labeled retinal ganglion cells in organotypic retinal explant cultures by two methods. Exp Eye Res 2023; 226:109311. [PMID: 36403849 PMCID: PMC11003390 DOI: 10.1016/j.exer.2022.109311] [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: 08/21/2022] [Revised: 10/09/2022] [Accepted: 11/08/2022] [Indexed: 11/18/2022]
Abstract
Retinal explant cultures provide a valuable system to study retinal function in vitro. This study established a new retinal explant culture method to prolong the survival of retinal ganglion cells (RGCs). Explants were prepared in two different ways: with or without optic nerve. Retinas from newborn mice that had received an injection of MitoTracker Red into the contralateral superior colliculus to label axonal mitochondria were cultured as organotypic culture for 7 days in vitro. At several time points during the culture, viability of RGCs was assessed by multi-electrode array recording, and morphology by immunohistochemical methods. During the culture, the thickness of the retinal tissue in both groups gradually decreased, however, the structure of the layers of the retina could be identified. Massive apoptosis in the retinal ganglion cell layer (GCL) appeared on the first day of culture, thereafter the number of apoptotic cells decreased. Glial activation was observed throughout the culture, and there was no difference in morphology between the two groups. RGCs loss was exacerbated on 3rdday of culture, and RGCs loss in retinal explants with preserved optic nerve was significantly lower than in retinas that did not preserve the optic nerve. More and longer-lasting mitochondrial signals were observed in the injured area of the optic nerve-preserving explants. Retinal explants provide an invaluable tool for studying retinal function and developing treatments for ocular diseases. The optic nerve-preserving culture helps preserve the integrity of RGCs. The higher number of mitochondria in the nerve-preserving cultures may help maintain viability of RGCs.
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Affiliation(s)
- Baoqi Hu
- Department of Ophthalmology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, 710061, China; Department of Ophthalmology, The First Affiliated Hospital of Northwest University, Xi'an, Shaanxi, 710002, China; Department of Ophthalmology, Xi'an No. 1 Hospital, Xi'an, Shaanxi, 710002, China
| | - Yaoyao Huang
- Department of Ophthalmology, The First Affiliated Hospital of Northwest University, Xi'an, Shaanxi, 710002, China; Department of Ophthalmology, Xi'an No. 1 Hospital, Xi'an, Shaanxi, 710002, China; Faculty of Life Sciences and Medicine, Northwest University, Xi'an, 710069, Shaanxi, China
| | - Tatjana C Jakobs
- Department of Ophthalmology, Massachusetts Eye and Ear Infirmary / Schepens Eye Research Institute, Harvard Medical School, 20 Staniford Street, Boston, MA, 02114, United States
| | - Qianyan Kang
- Department of Ophthalmology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, 710061, China
| | - Ziwei Lv
- Faculty of Life Sciences and Medicine, Northwest University, Xi'an, 710069, Shaanxi, China
| | - Wenxuan Liu
- Faculty of Life Sciences and Medicine, Northwest University, Xi'an, 710069, Shaanxi, China
| | - Rui Wang
- Department of Ophthalmology, The First Affiliated Hospital of Northwest University, Xi'an, Shaanxi, 710002, China; Department of Ophthalmology, Xi'an No. 1 Hospital, Xi'an, Shaanxi, 710002, China; Shaanxi Institute of Ophthalmology, Xi'an, Shaanxi, 710002, China.
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Retinal Layer Separation (ReLayS) method enables the molecular analysis of photoreceptor segments and cell bodies, as well as the inner retina. Sci Rep 2022; 12:20195. [PMID: 36424523 PMCID: PMC9691741 DOI: 10.1038/s41598-022-24586-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 11/17/2022] [Indexed: 11/27/2022] Open
Abstract
Understanding the physiology of the retina, and especially of the highly polarized photoreceptors, is essential not only to broaden our knowledge of the processes required for normal vision, but also to develop effective therapies to prevent or slow retinal degenerative diseases. However, the molecular analysis of photoreceptors is a challenge due to the heterogeneity of the retinal tissue and the lack of easy and reliable methods for cell separation. Here we present the ReLayS method-a simple technique for the separation of photoreceptor segments (PS) containing both inner and outer segments, outer nuclear layer (ONL), and inner retina (InR) that contains the remaining retinal layers. The layer-specific material isolated from a mouse half-retina with the ReLayS method was sufficient for protein isolation and Western blotting or RNA isolation and real-time PCR studies. The separation of PS, ONL, and InR was successfully validated by Western blotting and real-time PCR using proteins and genes with known expression profiles within the retina. Furthermore, the separation of the PS from the ONL enabled the detection of light-driven translocation of transducin from the PS to the soma. ReLayS is a simple and useful method to address protein and possibly metabolites distribution in photoreceptor compartments in various situations including development, ageing, and degenerative diseases.
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Forward genetic analysis using OCT screening identifies Sfxn3 mutations leading to progressive outer retinal degeneration in mice. Proc Natl Acad Sci U S A 2020; 117:12931-12942. [PMID: 32457148 DOI: 10.1073/pnas.1921224117] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Retinal disease and loss of vision can result from any disruption of the complex pathways controlling retinal development and homeostasis. Forward genetics provides an excellent tool to find, in an unbiased manner, genes that are essential to these processes. Using N-ethyl-N-nitrosourea mutagenesis in mice in combination with a screening protocol using optical coherence tomography (OCT) and automated meiotic mapping, we identified 11 mutations presumably causative of retinal phenotypes in genes previously known to be essential for retinal integrity. In addition, we found multiple statistically significant gene-phenotype associations that have not been reported previously and decided to target one of these genes, Sfxn3 (encoding sideroflexin-3), using CRISPR/Cas9 technology. We demonstrate, using OCT, light microscopy, and electroretinography, that two Sfxn3 -/- mouse lines developed progressive and severe outer retinal degeneration. Electron microscopy showed thinning of the retinal pigment epithelium and disruption of the external limiting membrane. Using single-cell RNA sequencing of retinal cells isolated from C57BL/6J mice, we demonstrate that Sfxn3 is expressed in several bipolar cell subtypes, retinal ganglion cells, and some amacrine cell subtypes but not significantly in Müller cells or photoreceptors. In situ hybridization confirmed these findings. Furthermore, pathway analysis suggests that Sfxn3 may be associated with synaptic homeostasis. Importantly, electron microscopy analysis showed disruption of synapses and synaptic ribbons in the outer plexiform layer of Sfxn3 -/- mice. Our work describes a previously unknown requirement for Sfxn3 in retinal function.
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