1
|
Bou Ghanem GO, Wareham LK, Calkins DJ. Addressing neurodegeneration in glaucoma: Mechanisms, challenges, and treatments. Prog Retin Eye Res 2024; 100:101261. [PMID: 38527623 DOI: 10.1016/j.preteyeres.2024.101261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 03/15/2024] [Accepted: 03/19/2024] [Indexed: 03/27/2024]
Abstract
Glaucoma is the leading cause of irreversible blindness globally. The disease causes vision loss due to neurodegeneration of the retinal ganglion cell (RGC) projection to the brain through the optic nerve. Glaucoma is associated with sensitivity to intraocular pressure (IOP). Thus, mainstay treatments seek to manage IOP, though many patients continue to lose vision. To address neurodegeneration directly, numerous preclinical studies seek to develop protective or reparative therapies that act independently of IOP. These include growth factors, compounds targeting metabolism, anti-inflammatory and antioxidant agents, and neuromodulators. Despite success in experimental models, many of these approaches fail to translate into clinical benefits. Several factors contribute to this challenge. Firstly, the anatomic structure of the optic nerve head differs between rodents, nonhuman primates, and humans. Additionally, animal models do not replicate the complex glaucoma pathophysiology in humans. Therefore, to enhance the success of translating these findings, we propose two approaches. First, thorough evaluation of experimental targets in multiple animal models, including nonhuman primates, should precede clinical trials. Second, we advocate for combination therapy, which involves using multiple agents simultaneously, especially in the early and potentially reversible stages of the disease. These strategies aim to increase the chances of successful neuroprotective treatment for glaucoma.
Collapse
Affiliation(s)
- Ghazi O Bou Ghanem
- Vanderbilt Eye Institute, Department of Ophthalmology and Visual Sciences, Vanderbilt University Medical Center, Nashville, TN, USA.
| | - Lauren K Wareham
- Vanderbilt Eye Institute, Department of Ophthalmology and Visual Sciences, Vanderbilt University Medical Center, Nashville, TN, USA.
| | - David J Calkins
- Vanderbilt Eye Institute, Department of Ophthalmology and Visual Sciences, Vanderbilt University Medical Center, Nashville, TN, USA.
| |
Collapse
|
2
|
Xuan M, Wang W, Bulloch G, Zhang J, Ha J, Wang Q, Wang J, Lin X, He M. Impact of Acute Ocular Hypertension on Retinal Ganglion Cell Loss in Mice. Transl Vis Sci Technol 2024; 13:17. [PMID: 38506800 PMCID: PMC10959197 DOI: 10.1167/tvst.13.3.17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Accepted: 02/07/2024] [Indexed: 03/21/2024] Open
Abstract
Purpose To assess the correlation between intraocular pressure (IOP) levels and retinal ganglion cell (RGC) loss across different fixed-duration episodes of acute ocular hypertension (AOH). Methods AOH was induced in Thy1-YFP-H transgenic mice by inserting a needle connected to a saline solution container into the anterior chamber. Thirty-one groups were tested, each comprising three to five mice exposed to IOP levels ranging from 50 to 110 mm Hg in 5/10 mm Hg increments for 60/90/120 minutes and a sham control group. The YFP-expressing RGCs were quantified by confocal scanning laser ophthalmoscopy, whereas peripapillary ganglion cell complex thickness was measured using spectral-domain optical coherence tomography. Changes in RGC count and GCCT were determined from values measured 30 days after AOH relative to baseline (before AOH). Results In the 60-minute AOH groups, RGC loss varied even when IOP was increased up to 110 mm Hg (36.8%-68.2%). However, for longer durations (90 and 120 minutes), a narrow range of IOP levels (60-70 mm Hg for 90-minute duration; 55-65 mm Hg for 120-minute duration) produced a significant difference in RGC loss, ranging from <25% to >90%. Additionally, loss of YFP-expressing RGCs was comparable to that of total RGCs in the same retinas. Conclusions Reproducible RGC loss during AOH depends on precise durations and IOP thresholds. In the current study, the optimal choice is an AOH protocol set at 70 mm Hg for a duration of 90 minutes. Translational Relevance This study can assist in determining the optimal duration and intensity of IOP for the effective utilization of AOH models.
Collapse
Affiliation(s)
- Meng Xuan
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, Guangdong, China
| | - Wei Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, Guangdong, China
| | - Gabriella Bulloch
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, Victoria, Australia
- Faculty of Science, Medicine and Health, University of Melbourne, Melbourne, Victoria, Australia
| | - Jian Zhang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, Guangdong, China
| | - Jason Ha
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, Victoria, Australia
| | - Qilin Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, Guangdong, China
| | - Juanjuan Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, Guangdong, China
| | - Xingyan Lin
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, Guangdong, China
| | - Mingguang He
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, Guangdong, China
- School of Optometry, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China
- Research Centre for SHARP Vision (RCSV), The Hong Kong Polytechnic University, Kowloon, Hong Kong, China
- Centre for Eye and Vision Research (CEVR), Hong Kong, China
| |
Collapse
|
3
|
Sun MT, Pershing S, Goldberg JL, Wang SY. Impact of Type 2 diabetes mellitus and insulin use on progression to glaucoma surgery in primary open angle glaucoma. Eye (Lond) 2024; 38:558-564. [PMID: 37740048 PMCID: PMC10858255 DOI: 10.1038/s41433-023-02734-2] [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: 02/09/2023] [Revised: 08/07/2023] [Accepted: 09/07/2023] [Indexed: 09/24/2023] Open
Abstract
PURPOSE To investigate outcomes of primary open-angle glaucoma (POAG) patients with and without type 2 diabetes mellitus (T2DM). METHODS Retrospective observational study using U.S. nationwide healthcare insurance claims database. Patients ≥40 years old with at least one HbA1c within one year of POAG diagnosis were included. Diabetic factors associated with POAG progression requiring glaucoma surgery were evaluated using multivariable Cox proportional hazards regression models adjusted for demographic, diabetic and glaucoma factors. T2DM diagnosis and use of either oral hypoglycaemic agents or insulin therapy were assessed in association with POAG progression requiring glaucoma surgery. RESULTS 104,515 POAG patients were included, of which 70,315 (67%) had T2DM. The mean age was 68.9 years (Standard deviation 9.2) and 55% were female. Of those with T2DM, 93% were taking medication (65,468); 95% (62,412) taking oral hypoglycaemic agents, and 34% (22,028) were on insulin. In multivariable analyses, patients with T2DM had a higher hazard of requiring glaucoma surgery (Hazard ratio, HR 1.15, 95% CI 1.09-1.21, p < 0.001). Higher mean HbA1c was also a significant predictor of progression requiring glaucoma surgery (HR 1.02, 95% CI 1.01-1.03, p < 0.001). When evaluating only patients who were taking antidiabetic medication, after adjusting for confounders, insulin use was associated with a 1.20 higher hazard of requiring glaucoma surgery compared to oral hypoglycaemic agents (95% CI 1.14-1.27, p < 0.001), but when stratified by HbA1c, this effect was only significant for those with HbA1c > 7.5%. CONCLUSIONS Higher baseline HbA1c, particularly in patients taking insulin may be associated with higher rates of glaucoma surgery in POAG.
Collapse
Affiliation(s)
- Michelle T Sun
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University, Palo Alto, CA, USA
| | - Suzann Pershing
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University, Palo Alto, CA, USA
| | - Jeffrey L Goldberg
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University, Palo Alto, CA, USA
| | - Sophia Y Wang
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University, Palo Alto, CA, USA.
| |
Collapse
|
4
|
Lei Q, Xiang K, Cheng L, Xiang M. Human retinal organoids with an OPA1 mutation are defective in retinal ganglion cell differentiation and function. Stem Cell Reports 2024; 19:68-83. [PMID: 38101398 PMCID: PMC10828684 DOI: 10.1016/j.stemcr.2023.11.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Revised: 11/15/2023] [Accepted: 11/16/2023] [Indexed: 12/17/2023] Open
Abstract
Autosomal dominant optic atrophy (ADOA), mostly caused by heterozygous OPA1 mutations and characterized by retinal ganglion cell (RGC) loss and optic nerve degeneration, is one of the most common types of inherited optic neuropathies. Previous work using a two-dimensional (2D) differentiation model of induced pluripotent stem cells (iPSCs) has investigated ADOA pathogenesis but failed to agree on the effect of OPA1 mutations on RGC differentiation. Here, we use 3D retinal organoids capable of mimicking in vivo retinal development to resolve the issue. We generated isogenic iPSCs carrying the hotspot OPA1 c.2708_2711delTTAG mutation and found that the mutant variant caused defective initial and terminal differentiation and abnormal electrophysiological properties of organoid-derived RGCs. Moreover, this variant inhibits progenitor proliferation and results in mitochondrial dysfunction. These data demonstrate that retinal organoids coupled with gene editing serve as a powerful tool to definitively identify disease-related phenotypes and provide valuable resources to further investigate ADOA pathogenesis and screen for ADOA therapeutics.
Collapse
Affiliation(s)
- Qiannan Lei
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou 510060, China
| | - Kangjian Xiang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou 510060, China
| | - Lin Cheng
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou 510060, China
| | - Mengqing Xiang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou 510060, China; Guangdong Provincial Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China.
| |
Collapse
|
5
|
Soucy JR, Aguzzi EA, Cho J, Gilhooley MJ, Keuthan C, Luo Z, Monavarfeshani A, Saleem MA, Wang XW, Wohlschlegel J, Baranov P, Di Polo A, Fortune B, Gokoffski KK, Goldberg JL, Guido W, Kolodkin AL, Mason CA, Ou Y, Reh TA, Ross AG, Samuels BC, Welsbie D, Zack DJ, Johnson TV. Retinal ganglion cell repopulation for vision restoration in optic neuropathy: a roadmap from the RReSTORe Consortium. Mol Neurodegener 2023; 18:64. [PMID: 37735444 PMCID: PMC10514988 DOI: 10.1186/s13024-023-00655-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 09/07/2023] [Indexed: 09/23/2023] Open
Abstract
Retinal ganglion cell (RGC) death in glaucoma and other optic neuropathies results in irreversible vision loss due to the mammalian central nervous system's limited regenerative capacity. RGC repopulation is a promising therapeutic approach to reverse vision loss from optic neuropathies if the newly introduced neurons can reestablish functional retinal and thalamic circuits. In theory, RGCs might be repopulated through the transplantation of stem cell-derived neurons or via the induction of endogenous transdifferentiation. The RGC Repopulation, Stem Cell Transplantation, and Optic Nerve Regeneration (RReSTORe) Consortium was established to address the challenges associated with the therapeutic repair of the visual pathway in optic neuropathy. In 2022, the RReSTORe Consortium initiated ongoing international collaborative discussions to advance the RGC repopulation field and has identified five critical areas of focus: (1) RGC development and differentiation, (2) Transplantation methods and models, (3) RGC survival, maturation, and host interactions, (4) Inner retinal wiring, and (5) Eye-to-brain connectivity. Here, we discuss the most pertinent questions and challenges that exist on the path to clinical translation and suggest experimental directions to propel this work going forward. Using these five subtopic discussion groups (SDGs) as a framework, we suggest multidisciplinary approaches to restore the diseased visual pathway by leveraging groundbreaking insights from developmental neuroscience, stem cell biology, molecular biology, optical imaging, animal models of optic neuropathy, immunology & immunotolerance, neuropathology & neuroprotection, materials science & biomedical engineering, and regenerative neuroscience. While significant hurdles remain, the RReSTORe Consortium's efforts provide a comprehensive roadmap for advancing the RGC repopulation field and hold potential for transformative progress in restoring vision in patients suffering from optic neuropathies.
Collapse
Affiliation(s)
- Jonathan R Soucy
- Department of Ophthalmology, Schepens Eye Research Institute of Mass. Eye and Ear, Harvard Medical School, Boston, MA, USA
| | - Erika A Aguzzi
- The Institute of Ophthalmology, University College London, London, England, UK
| | - Julie Cho
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Michael James Gilhooley
- The Institute of Ophthalmology, University College London, London, England, UK
- Moorfields Eye Hospital, London, England, UK
| | - Casey Keuthan
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Ziming Luo
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Aboozar Monavarfeshani
- Center for Brain Science and Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA
- Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA
| | - Meher A Saleem
- Bascom Palmer Eye Institute, University of Miami Health System, Miami, FL, USA
| | - Xue-Wei Wang
- Department of Orthopaedic Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | | | - Petr Baranov
- Department of Ophthalmology, Schepens Eye Research Institute of Mass. Eye and Ear, Harvard Medical School, Boston, MA, USA
| | - Adriana Di Polo
- Department of Neuroscience, University of Montreal, Montreal, QC, Canada
- University of Montreal Hospital Research Centre, Montreal, QC, Canada
| | - Brad Fortune
- Discoveries in Sight Research Laboratories, Devers Eye Institute and Legacy Research Institute, Legacy Health, Portland, OR, USA
| | - Kimberly K Gokoffski
- Department of Ophthalmology, Roski Eye Institute, University of Southern California, Los Angeles, CA, USA
| | - Jeffrey L Goldberg
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA
| | - William Guido
- Department of Anatomical Sciences and Neurobiology, School of Medicine, University of Louisville, Louisville, KY, USA
| | - Alex L Kolodkin
- The Solomon H Snyder, Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Carol A Mason
- Departments of Pathology and Cell Biology, Neuroscience, and Ophthalmology, College of Physicians and Surgeons, Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA
| | - Yvonne Ou
- Department of Ophthalmology, University of California, San Francisco, CA, USA
| | - Thomas A Reh
- Department of Biological Structure, University of Washington, Seattle, WA, USA
| | - Ahmara G Ross
- Departments of Ophthalmology and Neurology, University of Pennsylvania, Philadelphia, PA, USA
| | - Brian C Samuels
- Department of Ophthalmology and Visual Sciences, Callahan Eye Hospital, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Derek Welsbie
- Shiley Eye Institute and Viterbi Family Department of Ophthalmology, University of California, San Diego, CA, USA
| | - Donald J Zack
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, 21287 MD, USA
- Departments of Neuroscience, Molecular Biology & Genetics, and Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Thomas V Johnson
- Departments of Neuroscience, Molecular Biology & Genetics, and Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
- Cellular & Molecular Medicine Program, Johns Hopkins University School of Medicine, Baltimore, 21287 MD, USA.
| |
Collapse
|
6
|
Jiménez-Loygorri JI, Benítez-Fernández R, Viedma-Poyatos Á, Zapata-Muñoz J, Villarejo-Zori B, Gómez-Sintes R, Boya P. Mitophagy in the retina: Viewing mitochondrial homeostasis through a new lens. Prog Retin Eye Res 2023; 96:101205. [PMID: 37454969 DOI: 10.1016/j.preteyeres.2023.101205] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 07/11/2023] [Accepted: 07/13/2023] [Indexed: 07/18/2023]
Abstract
Mitochondrial function is key to support metabolism and homeostasis in the retina, an organ that has one of the highest metabolic rates body-wide and is constantly exposed to photooxidative damage and external stressors. Mitophagy is the selective autophagic degradation of mitochondria within lysosomes, and can be triggered by distinct stimuli such as mitochondrial damage or hypoxia. Here, we review the importance of mitophagy in retinal physiology and pathology. In the developing retina, mitophagy is essential for metabolic reprogramming and differentiation of retina ganglion cells (RGCs). In basal conditions, mitophagy acts as a quality control mechanism, maintaining a healthy mitochondrial pool to meet cellular demands. We summarize the different autophagy- and mitophagy-deficient mouse models described in the literature, and discuss the potential role of mitophagy dysregulation in retinal diseases such as glaucoma, diabetic retinopathy, retinitis pigmentosa, and age-related macular degeneration. Finally, we provide an overview of methods used to monitor mitophagy in vitro, ex vivo, and in vivo. This review highlights the important role of mitophagy in sustaining visual function, and its potential as a putative therapeutic target for retinal and other diseases.
Collapse
Affiliation(s)
- Juan Ignacio Jiménez-Loygorri
- Autophagy Lab, Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas Margarita Salas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain.
| | - Rocío Benítez-Fernández
- Autophagy Lab, Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas Margarita Salas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain; Departament of Neuroscience and Movement Science, Faculty of Science and Medicine, University of Fribourg, 1700, Fribourg, Switzerland
| | - Álvaro Viedma-Poyatos
- Autophagy Lab, Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas Margarita Salas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Juan Zapata-Muñoz
- Autophagy Lab, Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas Margarita Salas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Beatriz Villarejo-Zori
- Autophagy Lab, Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas Margarita Salas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Raquel Gómez-Sintes
- Autophagy Lab, Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas Margarita Salas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Patricia Boya
- Autophagy Lab, Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas Margarita Salas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain; Departament of Neuroscience and Movement Science, Faculty of Science and Medicine, University of Fribourg, 1700, Fribourg, Switzerland.
| |
Collapse
|
7
|
Soliño M, Yu A, Della Santina L, Ou Y. Large-scale survey of excitatory synapses reveals sublamina-specific and asymmetric synapse disassembly in a neurodegenerative circuit. iScience 2023; 26:107262. [PMID: 37609630 PMCID: PMC10440711 DOI: 10.1016/j.isci.2023.107262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 05/09/2023] [Accepted: 06/27/2023] [Indexed: 08/24/2023] Open
Abstract
In the nervous system, parallel circuits are organized in part by the lamina-specific compartmentalization of synaptic connections. In sensory systems such as mammalian retina, degenerating third-order neurons remodel their local presynaptic connectivity with second-order neurons. To determine whether there are sublamina-specific perturbations after injury of adult retinal ganglion cells, we comprehensively analyzed excitatory synapses across the inner plexiform layer (IPL) where bipolar cells connect to ganglion cells. Here, we show that pre- and postsynaptic component loss occurs throughout the IPL in a sublamina-dependent fashion after transient intraocular pressure elevation. Partnered synaptic components are lost as neurodegeneration progresses, while unpartnered synaptic components remain stable. Furthermore, presynaptic components are either lost first or simultaneously with the postsynaptic component. Our results demonstrate that this degenerating neural circuit exhibits differential vulnerability of excitatory synapses depending on IPL depth, highlighting the ordered disassembly of synapses that is specific to laminar compartments of the retina.
Collapse
Affiliation(s)
- Manuel Soliño
- Department of Ophthalmology, University of California San Francisco School of Medicine, San Francisco, CA 94143, USA
| | - Alfred Yu
- Department of Ophthalmology, University of California San Francisco School of Medicine, San Francisco, CA 94143, USA
| | - Luca Della Santina
- Department of Ophthalmology, University of California San Francisco School of Medicine, San Francisco, CA 94143, USA
- College of Optometry, University of Houston, Houston, TX 77204, USA
| | - Yvonne Ou
- Department of Ophthalmology, University of California San Francisco School of Medicine, San Francisco, CA 94143, USA
| |
Collapse
|
8
|
Tribble JR, Hui F, Quintero H, El Hajji S, Bell K, Di Polo A, Williams PA. Neuroprotection in glaucoma: Mechanisms beyond intraocular pressure lowering. Mol Aspects Med 2023; 92:101193. [PMID: 37331129 DOI: 10.1016/j.mam.2023.101193] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 05/25/2023] [Accepted: 06/04/2023] [Indexed: 06/20/2023]
Abstract
Glaucoma is a common, complex, multifactorial neurodegenerative disease characterized by progressive dysfunction and then loss of retinal ganglion cells, the output neurons of the retina. Glaucoma is the most common cause of irreversible blindness and affects ∼80 million people worldwide with many more undiagnosed. The major risk factors for glaucoma are genetics, age, and elevated intraocular pressure. Current strategies only target intraocular pressure management and do not directly target the neurodegenerative processes occurring at the level of the retinal ganglion cell. Despite strategies to manage intraocular pressure, as many as 40% of glaucoma patients progress to blindness in at least one eye during their lifetime. As such, neuroprotective strategies that target the retinal ganglion cell and these neurodegenerative processes directly are of great therapeutic need. This review will cover the recent advances from basic biology to on-going clinical trials for neuroprotection in glaucoma covering degenerative mechanisms, metabolism, insulin signaling, mTOR, axon transport, apoptosis, autophagy, and neuroinflammation. With an increased understanding of both the basic and clinical mechanisms of the disease, we are closer than ever to a neuroprotective strategy for glaucoma.
Collapse
Affiliation(s)
- James R Tribble
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden
| | - Flora Hui
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Australia; Department of Optometry & Vision Sciences, The University of Melbourne, Melbourne, Australia
| | - Heberto Quintero
- Department of Neuroscience, University of Montreal, Montreal, Canada; Neuroscience Division, Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, Canada
| | - Sana El Hajji
- Department of Neuroscience, University of Montreal, Montreal, Canada; Neuroscience Division, Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, Canada
| | - Katharina Bell
- NHMRC Clinical Trials Centre, University of Sydney, Australia; Eye ACP Duke-NUS, Singapore
| | - Adriana Di Polo
- Department of Neuroscience, University of Montreal, Montreal, Canada; Neuroscience Division, Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, Canada
| | - Pete A Williams
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden.
| |
Collapse
|
9
|
Van Dyck A, Masin L, Bergmans S, Schevenels G, Beckers A, Vanhollebeke B, Moons L. A new microfluidic model to study dendritic remodeling and mitochondrial dynamics during axonal regeneration of adult zebrafish retinal neurons. Front Mol Neurosci 2023; 16:1196504. [PMID: 37396787 PMCID: PMC10307971 DOI: 10.3389/fnmol.2023.1196504] [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: 03/29/2023] [Accepted: 05/10/2023] [Indexed: 07/04/2023] Open
Abstract
Unlike mammals, adult zebrafish are able to fully regenerate axons and functionally recover from neuronal damage in the mature central nervous system (CNS). Decades of research have tried to identify the mechanisms behind their spontaneous regenerative capacity, but the exact underlying pathways and molecular drivers remain to be fully elucidated. By studying optic nerve injury-induced axonal regrowth of adult zebrafish retinal ganglion cells (RGCs), we previously reported transient dendritic shrinkage and changes in the distribution and morphology of mitochondria in the different neuronal compartments throughout the regenerative process. These data suggest that dendrite remodeling and temporary changes in mitochondrial dynamics contribute to effective axonal and dendritic repair upon optic nerve injury. To further elucidate these interactions, we here present a novel adult zebrafish microfluidic model in which we can demonstrate compartment-specific alterations in resource allocation in real-time at single neuron level. First, we developed a pioneering method that enables to isolate and culture adult zebrafish retinal neurons in a microfluidic setup. Notably, with this protocol, we report on a long-term adult primary neuronal culture with a high number of surviving and spontaneously outgrowing mature neurons, which was thus far only very limitedly described in literature. By performing time-lapse live cell imaging and kymographic analyses in this setup, we can explore changes in dendritic remodeling and mitochondrial motility during spontaneous axonal regeneration. This innovative model system will enable to discover how redirecting intraneuronal energy resources supports successful regeneration in the adult zebrafish CNS, and might facilitate the discovery of new therapeutic targets to promote neuronal repair in humans.
Collapse
Affiliation(s)
- Annelies Van Dyck
- Neural Circuit Development and Regeneration Research Group, Animal Physiology and Neurobiology Division, Department of Biology, Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Luca Masin
- Neural Circuit Development and Regeneration Research Group, Animal Physiology and Neurobiology Division, Department of Biology, Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Steven Bergmans
- Neural Circuit Development and Regeneration Research Group, Animal Physiology and Neurobiology Division, Department of Biology, Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Giel Schevenels
- Laboratory of Neurovascular Signaling, Department of Molecular Biology, ULB Neuroscience Institute, Université libre de Bruxelles, Gosselies, Belgium
| | - An Beckers
- Neural Circuit Development and Regeneration Research Group, Animal Physiology and Neurobiology Division, Department of Biology, Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Benoit Vanhollebeke
- Laboratory of Neurovascular Signaling, Department of Molecular Biology, ULB Neuroscience Institute, Université libre de Bruxelles, Gosselies, Belgium
| | - Lieve Moons
- Neural Circuit Development and Regeneration Research Group, Animal Physiology and Neurobiology Division, Department of Biology, Leuven Brain Institute, KU Leuven, Leuven, Belgium
| |
Collapse
|
10
|
Lawrence ECN, Guo M, Schwartz TD, Wu J, Lu J, Nikonov S, Sterling JK, Cui QN. Topical and systemic GLP-1R agonist administration both rescue retinal ganglion cells in hypertensive glaucoma. Front Cell Neurosci 2023; 17:1156829. [PMID: 37362000 PMCID: PMC10288152 DOI: 10.3389/fncel.2023.1156829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 05/05/2023] [Indexed: 06/28/2023] Open
Abstract
Glaucomatous neurodegeneration, a blinding disease affecting millions worldwide, has a need for the exploration of new and effective therapies. Previously, the glucagon-like peptide-1 receptor (GLP-1R) agonist NLY01 was shown to reduce microglia/macrophage activation, rescuing retinal ganglion cells after IOP elevation in an animal model of glaucoma. GLP-1R agonist use is also associated with a reduced risk for glaucoma in patients with diabetes. In this study, we demonstrate that several commercially available GLP-1R agonists, administered either systemically or topically, hold protective potential in a mouse model of hypertensive glaucoma. Further, the resulting neuroprotection likely occurs through the same pathways previously shown for NLY01. This work contributes to a growing body of evidence suggesting that GLP-1R agonists represent a viable therapeutic option for glaucoma.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | - Qi N. Cui
- Department of Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, PA, United States
| |
Collapse
|
11
|
Tang VTS, Symons RCA, Fourlanos S, Guest D, McKendrick AM. Contrast Increment and Decrement Processing in Individuals With and Without Diabetes. Invest Ophthalmol Vis Sci 2023; 64:26. [PMID: 37083950 PMCID: PMC10132322 DOI: 10.1167/iovs.64.4.26] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/22/2023] Open
Abstract
Purpose Animal models suggest that ON retinal ganglion cells (RGCs) may be more vulnerable to diabetic insult than OFF cells. Using three psychophysical tasks to infer the function of ON and OFF RGCs, we hypothesized that functional responses to contrast increments will be preferentially affected in early diabetes mellitus (DM) compared to contrast decrement responses. Methods Fifty-two people with DM (type 1 or type 2) (mean age = 34.8 years, range = 18-60 years) and 48 age-matched controls (mean age = 35.4 years, range = 18-60 years) participated. Experiment 1 measured contrast sensitivity to increments and decrements at four visual field locations. Experiments 2 and 3 measured visual temporal processing using (i) a response time (RT) task, and (ii) a temporal order judgment task. Mean RT and accuracy were collected for experiment 2, whereas experiment 3 measured temporal thresholds. Results For experiment 1, the DM group showed reduced increment and decrement contrast sensitivity (F (1, 97) = 4.04, P = 0.047) especially for the central location. For experiment 2, those with DM demonstrated slower RT and lower response accuracies to increments and decrements (increments: U = 780, P = 0.01, decrements: U = 749, P = 0.005). For experiment 3, performance was similar between groups (F (1, 91) = 2.52, P = 0.137). Conclusions When assessed cross-sectionally, nonselective functional consequences of retinal neuron damage are present in early DM, particularly for foveal testing. Whether increment-decrement functional indices relate to diabetic retinopathy (DR) progression or poorer visual prognosis in DM requires further study.
Collapse
Affiliation(s)
- Vanessa Thien Sze Tang
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Australia
| | - Robert Charles Andrew Symons
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Australia
- Department of Surgery, The University of Melbourne, Parkville, Australia
- Centre for Eye Research Australia, East Melbourne, Australia
- Department of Surgery, Alfred Hospital, Monash University, Australia
| | - Spiros Fourlanos
- Department Diabetes and Endocrinology, Royal Melbourne Hospital, Parkville, Australia
- Department Medicine, Royal Melbourne Hospital, The University of Melbourne, Parkville, Australia
- Australian Centre for Accelerating Diabetes Innovations, The University of Melbourne, Parkville, Australia
| | - Daryl Guest
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Australia
| | - Allison Maree McKendrick
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Australia
- Division of Optometry, University of Western Australia, Perth, Australia
- Lions Eye Institute, Nedlands, Australia
| |
Collapse
|
12
|
Liu X, Zhao Y, Zou W. Molecular mechanisms of neurite regeneration and repair: insights from C. elegans and Drosophila. CELL REGENERATION (LONDON, ENGLAND) 2023; 12:12. [PMID: 37005942 PMCID: PMC10067779 DOI: 10.1186/s13619-022-00155-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 12/01/2022] [Indexed: 04/04/2023]
Abstract
The difficulties of injured and degenerated neurons to regenerate neurites and regain functions are more significant than in other body tissues, making neurodegenerative and related diseases hard to cure. Uncovering the secrets of neural regeneration and how this process may be inhibited after injury will provide insights into novel management and potential treatments for these diseases. Caenorhabditis elegans and Drosophila melanogaster are two of the most widely used and well-established model organisms endowed with advantages in genetic manipulation and live imaging to explore this fundamental question about neural regeneration. Here, we review the classical models and techniques, and the involvement and cooperation of subcellular structures during neurite regeneration using these two organisms. Finally, we list several important open questions that we look forward to inspiring future research.
Collapse
Affiliation(s)
- Xiaofan Liu
- The Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu, China
- Institute of Translational Medicine, Zhejiang University, Hangzhou, China
| | - Yuqing Zhao
- The Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu, China
- Institute of Translational Medicine, Zhejiang University, Hangzhou, China
- Institute of Zhejiang University and University of Edinburgh, Jiaxing, China
| | - Wei Zou
- The Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu, China.
- Institute of Translational Medicine, Zhejiang University, Hangzhou, China.
| |
Collapse
|
13
|
Hnilicova P, Kantorova E, Sutovsky S, Grofik M, Zelenak K, Kurca E, Zilka N, Parvanovova P, Kolisek M. Imaging Methods Applicable in the Diagnostics of Alzheimer's Disease, Considering the Involvement of Insulin Resistance. Int J Mol Sci 2023; 24:ijms24043325. [PMID: 36834741 PMCID: PMC9958721 DOI: 10.3390/ijms24043325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2022] [Revised: 01/29/2023] [Accepted: 01/30/2023] [Indexed: 02/10/2023] Open
Abstract
Alzheimer's disease (AD) is an incurable neurodegenerative disease and the most frequently diagnosed type of dementia, characterized by (1) perturbed cerebral perfusion, vasculature, and cortical metabolism; (2) induced proinflammatory processes; and (3) the aggregation of amyloid beta and hyperphosphorylated Tau proteins. Subclinical AD changes are commonly detectable by using radiological and nuclear neuroimaging methods such as magnetic resonance imaging (MRI), computed tomography (CT), positron emission tomography (PET), and single-photon emission computed tomography (SPECT). Furthermore, other valuable modalities exist (in particular, structural volumetric, diffusion, perfusion, functional, and metabolic magnetic resonance methods) that can advance the diagnostic algorithm of AD and our understanding of its pathogenesis. Recently, new insights into AD pathoetiology revealed that deranged insulin homeostasis in the brain may play a role in the onset and progression of the disease. AD-related brain insulin resistance is closely linked to systemic insulin homeostasis disorders caused by pancreas and/or liver dysfunction. Indeed, in recent studies, linkages between the development and onset of AD and the liver and/or pancreas have been established. Aside from standard radiological and nuclear neuroimaging methods and clinically fewer common methods of magnetic resonance, this article also discusses the use of new suggestive non-neuronal imaging modalities to assess AD-associated structural changes in the liver and pancreas. Studying these changes might be of great clinical importance because of their possible involvement in AD pathogenesis during the prodromal phase of the disease.
Collapse
Affiliation(s)
- Petra Hnilicova
- Biomedical Center Martin, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, 036 01 Martin, Slovakia
- Correspondence: (P.H.); (M.K.)
| | - Ema Kantorova
- Clinic of Neurology, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, 036 01 Martin, Slovakia
| | - Stanislav Sutovsky
- 1st Department of Neurology, Faculty of Medicine, Comenius University in Bratislava and University Hospital, 813 67 Bratislava, Slovakia
| | - Milan Grofik
- Clinic of Neurology, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, 036 01 Martin, Slovakia
| | - Kamil Zelenak
- Clinic of Radiology, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, 036 01 Martin, Slovakia
| | - Egon Kurca
- Clinic of Neurology, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, 036 01 Martin, Slovakia
| | - Norbert Zilka
- Institute of Neuroimmunology, Slovak Academy of Sciences, 845 10 Bratislava, Slovakia
| | - Petra Parvanovova
- Department of Medical Biochemistry, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, 036 01 Martin, Slovakia
| | - Martin Kolisek
- Biomedical Center Martin, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, 036 01 Martin, Slovakia
- Correspondence: (P.H.); (M.K.)
| |
Collapse
|
14
|
Huang KC, Gomes C, Shiga Y, Belforte N, VanderWall KB, Lavekar SS, Fligor CM, Harkin J, Di Polo A, Meyer JS. Autophagy disruption reduces mTORC1 activation leading to retinal ganglion cell neurodegeneration associated with glaucoma. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.04.522687. [PMID: 36711831 PMCID: PMC9881969 DOI: 10.1101/2023.01.04.522687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Autophagy dysfunction has been associated with several neurodegenerative diseases including glaucoma, characterized by the degeneration of retinal ganglion cells (RGCs). However, the mechanisms by which autophagy dysfunction promotes RGC damage remain unclear. Here, we hypothesized that perturbation of the autophagy pathway results in increased autophagic demand, thereby downregulating signaling through mammalian target of rapamycin complex 1 (mTORC1), a negative regulator of autophagy, contributing to the degeneration of RGCs. We identified an impairment of autophagic-lysosomal degradation and decreased mTORC1 signaling via activation of the stress sensor adenosine monophosphate-activated protein kinase (AMPK), along with subsequent neurodegeneration in RGCs differentiated from human pluripotent stem cells (hPSCs) with a glaucoma-associated variant of Optineurin (OPTN-E50K). Similarly, the microbead occlusion model of glaucoma resulting in ocular hypertension also exhibited autophagy disruption and mTORC1 downregulation. Pharmacological inhibition of mTORC1 in hPSC-derived RGCs recapitulated disease-related neurodegenerative phenotypes in otherwise healthy RGCs, while the mTOR-independent induction of autophagy reduced protein accumulation and restored neurite outgrowth in diseased OPTN-E50K RGCs. Taken together, these results highlight an important balance between autophagy and mTORC1 signaling essential for RGC homeostasis, while disruption to these pathways contributes to neurodegenerative features in glaucoma, providing a potential therapeutic target to prevent neurodegeneration.
Collapse
Affiliation(s)
- Kang-Chieh Huang
- Department of Biology, Indiana University Purdue University Indianapolis, Indianapolis IN USA
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis IN USA
| | - Cátia Gomes
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis IN USA
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis IN USA
| | - Yukihiro Shiga
- Department of Neuroscience, University of Montreal, Montreal, Quebec, Canada
- University of Montreal Hospital Research Centre, Montreal, Quebec, Canada
| | - Nicolas Belforte
- Department of Neuroscience, University of Montreal, Montreal, Quebec, Canada
- University of Montreal Hospital Research Centre, Montreal, Quebec, Canada
| | - Kirstin B. VanderWall
- Department of Biology, Indiana University Purdue University Indianapolis, Indianapolis IN USA
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis IN USA
| | - Sailee S. Lavekar
- Department of Biology, Indiana University Purdue University Indianapolis, Indianapolis IN USA
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis IN USA
| | - Clarisse M. Fligor
- Department of Biology, Indiana University Purdue University Indianapolis, Indianapolis IN USA
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis IN USA
| | - Jade Harkin
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis IN USA
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis IN USA
| | - Adriana Di Polo
- Department of Neuroscience, University of Montreal, Montreal, Quebec, Canada
- University of Montreal Hospital Research Centre, Montreal, Quebec, Canada
| | - Jason S. Meyer
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis IN USA
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis IN USA
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis IN USA
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis IN USA
| |
Collapse
|
15
|
Huang KC, Gomes C, Meyer JS. Retinal Ganglion Cells in a Dish: Current Strategies and Recommended Best Practices for Effective In Vitro Modeling of Development and Disease. Handb Exp Pharmacol 2023; 281:83-102. [PMID: 36907969 PMCID: PMC10497719 DOI: 10.1007/164_2023_642] [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] [Indexed: 03/14/2023]
Abstract
The ability to derive retinal ganglion cells (RGCs) from human pluripotent stem cells (hPSCs) provides an extraordinary opportunity to study the development of RGCs as well as cellular mechanisms underlying their degeneration in optic neuropathies. In the past several years, multiple approaches have been established that allow for the generation of RGCs from hPSCs, with these methods greatly improved in more recent studies to yield mature RGCs that more faithfully recapitulate phenotypes within the eye. Nevertheless, numerous differences still remain between hPSC-RGCs and those found within the human eye, with these differences likely explained at least in part due to the environment in which hPSC-RGCs are grown. With the ultimate goal of generating hPSC-RGCs that most closely resemble those within the retina for proper studies of retinal development, disease modeling, as well as cellular replacement, we review within this manuscript the current effective approaches for the differentiation of hPSC-RGCs, as well as how they have been applied for the investigation of RGC neurodegenerative diseases such as glaucoma. Furthermore, we provide our opinions on the characteristics of RGCs necessary for their use as effective in vitro disease models and importantly, how these current systems should be improved to more accurately reflect disease states. The establishment of characteristics in differentiated hPSC-RGCs that more effectively mimic RGCs within the retina will not only enable their use as effective models of RGC development, but will also create a better disease model for the identification of mechanisms underlying the neurodegeneration of RGCs in disease states such as glaucoma, further facilitating the development of therapeutic approaches to rescue RGCs from degeneration in disease states.
Collapse
Affiliation(s)
- Kang-Chieh Huang
- Department of Biology, Indiana University Purdue University Indianapolis, Indianapolis, IN, USA
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Cátia Gomes
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Jason S Meyer
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA.
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA.
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN, USA.
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, IN, USA.
| |
Collapse
|
16
|
Mohammadi M, Su E, Chew L, Mohammadzadeh V, Caprioli J, Weiss RE, Nouri-Mahdavi K. Comparison of Ganglion Cell Layer and Inner Plexiform Layer Rates of Change in Suspected and Established Glaucoma. Am J Ophthalmol 2022; 249:12-20. [PMID: 36516918 PMCID: PMC10106372 DOI: 10.1016/j.ajo.2022.12.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 11/28/2022] [Accepted: 12/05/2022] [Indexed: 12/14/2022]
Abstract
PURPOSE We compared ganglion cell layer (GCL) and inner plexiform layer (IPL) rates of change (RoC) in patients with glaucoma suspect (GS) and established glaucoma (EG) to test the hypothesis that IPL thickness changes would occur earlier than GCL changes in eyes with early damage. DESIGN Prospective, cohort study. METHODS A total of 64 GS eyes (46 patients) and 112 EG eyes (112 patients) with ≥2 years of follow-up and ≥3 macular optical coherence tomography scans were included. GCL and IPL superpixel thickness measurements were exported. A Bayesian hierarchical model with random intercepts/slopes and random residual variances was fitted to estimate RoC in individual superpixels. Normalized RoC and proportions of superpixels with significantly negative and positive GCL and IPL RoC were compared within the groups. RESULTS The average (SD) follow-up time and number of scans were 3.5 (0.7) years and 4.2 (1.0), respectively, in the GS group and 3.6 (0.4) years and 7.3 (1.1) in the EG group. Mean (SD) normalized RoC was faster for GCL than IPL (-0.69 [0.05] vs -0.33 [0.04]) in the GS group, whereas it was faster for IPL (-0.47 [0.03] vs -0.28 [0.02]) in EG eyes. GCL RoC were significantly negative in 24 of 36 superpixels compared with 8 of 36 for IPL (P < .001) in GS eyes. In the EG group, 23 of 36 superpixels had significant negative IPL RoC compared with 13 of 36 superpixels for GCL (P = .006). CONCLUSIONS GCL thickness is more likely to demonstrate change over time compared with IPL in glaucoma suspects. There is no evidence of preferential IPL thinning in eyes with suspected early glaucoma damage.
Collapse
Affiliation(s)
- Massood Mohammadi
- From the Glaucoma Division, Stein Eye Institute, David Geffen School of Medicine (M.M., L.C., V.M., J.C., K.N-M.), University of California Los Angeles, Los Angeles, California, USA
| | - Erica Su
- Department of Biostatistics, Fielding School of Public Health (E.S., R.E.W.), University of California Los Angeles, Los Angeles, California, USA
| | - Leila Chew
- From the Glaucoma Division, Stein Eye Institute, David Geffen School of Medicine (M.M., L.C., V.M., J.C., K.N-M.), University of California Los Angeles, Los Angeles, California, USA
| | - Vahid Mohammadzadeh
- From the Glaucoma Division, Stein Eye Institute, David Geffen School of Medicine (M.M., L.C., V.M., J.C., K.N-M.), University of California Los Angeles, Los Angeles, California, USA
| | - Joseph Caprioli
- From the Glaucoma Division, Stein Eye Institute, David Geffen School of Medicine (M.M., L.C., V.M., J.C., K.N-M.), University of California Los Angeles, Los Angeles, California, USA
| | - Robert E Weiss
- Department of Biostatistics, Fielding School of Public Health (E.S., R.E.W.), University of California Los Angeles, Los Angeles, California, USA
| | - Kouros Nouri-Mahdavi
- From the Glaucoma Division, Stein Eye Institute, David Geffen School of Medicine (M.M., L.C., V.M., J.C., K.N-M.), University of California Los Angeles, Los Angeles, California, USA.
| |
Collapse
|
17
|
Chau DDL, Li W, Chan WWR, Sun JKL, Zhai Y, Chow HM, Lau KF. Insulin stimulates atypical protein kinase C-mediated phosphorylation of the neuronal adaptor FE65 to potentiate neurite outgrowth by activating ARF6-Rac1 signaling. FASEB J 2022; 36:e22594. [PMID: 36250347 DOI: 10.1096/fj.202200757r] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 08/21/2022] [Accepted: 09/26/2022] [Indexed: 11/11/2022]
Abstract
Neurite outgrowth is a fundamental process in neurons that produces extensions and, consequently, neural connectivity. Neurite damage and atrophy are observed in various brain injuries and disorders. Understanding the intrinsic pathways of neurite outgrowth is essential for developing strategies to stimulate neurite regeneration. Insulin is a pivotal hormone in the regulation of glucose homeostasis. There is increasing evidence for the neurotrophic functions of insulin, including the induction of neurite outgrowth. However, the associated mechanism remains elusive. Here, we demonstrate that insulin potentiates neurite outgrowth mediated by the small GTPases ADP-ribosylation factor 6 (ARF6) and Ras-related C3 botulinum toxin substrate 1 (Rac1) through the neuronal adaptor FE65. Moreover, insulin enhances atypical protein kinase Cι/λ (PKCι/λ) activation and FE65 phosphorylation at serine 459 (S459) in neurons and mouse brains. In vitro and cellular assays show that PKCι/λ phosphorylated FE65 at S459. Consistently, insulin potentiates FE65 S459 phosphorylation only in the presence of PKCι/λ. Phosphomimetic studies show that an FE65 S459E mutant potently activates ARF6, Rac1, and neurite outgrowth. Notably, this phosphomimetic mutation enhances the FE65-ARF6 interaction, a process that promotes ARF6-Rac1-mediated neurite outgrowth. Likewise, insulin treatment and PKCι/λ overexpression potentiate the FE65-ARF6 interaction. Conversely, PKCι/λ knockdown suppresses the stimulatory effect of FE65 on ARF6-Rac1-mediated neurite outgrowth. The effect of insulin on neurite outgrowth is also markedly attenuated in PKCι/λ knockdown neurons, in the presence and absence of FE65. Our findings reveal a novel mechanism linking insulin with ARF6-Rac1-dependent neurite extension through the PKCι/λ-mediated phosphorylation of FE65.
Collapse
Affiliation(s)
- Dennis Dik-Long Chau
- School of Life Sciences, Faculty of Science, The Chinese University of Hong Kong, Hong Kong, China
| | - Wen Li
- School of Life Sciences, Faculty of Science, The Chinese University of Hong Kong, Hong Kong, China.,Research Laboratory for Biomedical Optics and Molecular Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Wai Wa Ray Chan
- School of Life Sciences, Faculty of Science, The Chinese University of Hong Kong, Hong Kong, China
| | - Jacquelyne Ka-Li Sun
- School of Life Sciences, Faculty of Science, The Chinese University of Hong Kong, Hong Kong, China
| | - Yuqi Zhai
- School of Life Sciences, Faculty of Science, The Chinese University of Hong Kong, Hong Kong, China
| | - Hei-Man Chow
- School of Life Sciences, Faculty of Science, The Chinese University of Hong Kong, Hong Kong, China
| | - Kwok-Fai Lau
- School of Life Sciences, Faculty of Science, The Chinese University of Hong Kong, Hong Kong, China
| |
Collapse
|
18
|
Faiq MA, Sengupta T, Nath M, Velpandian T, Saluja D, Dada R, Dada T, Chan KC. Ocular manifestations of central insulin resistance. Neural Regen Res 2022; 18:1139-1146. [PMID: 36255004 PMCID: PMC9827783 DOI: 10.4103/1673-5374.355765] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Central insulin resistance, the diminished cellular sensitivity to insulin in the brain, has been implicated in diabetes mellitus, Alzheimer's disease and other neurological disorders. However, whether and how central insulin resistance plays a role in the eye remains unclear. Here, we performed intracerebroventricular injection of S961, a potent and specific blocker of insulin receptor in adult Wistar rats to test if central insulin resistance leads to pathological changes in ocular structures. 80 mg of S961 was stereotaxically injected into the lateral ventricle of the experimental group twice at 7 days apart, whereas buffer solution was injected to the sham control group. Blood samples, intraocular pressure, trabecular meshwork morphology, ciliary body markers, retinal and optic nerve integrity, and whole genome expression patterns were then evaluated. While neither blood glucose nor serum insulin level was significantly altered in the experimental or control group, we found that injection of S961 but not buffer solution significantly increased intraocular pressure at 14 and 24 days after first injection, along with reduced porosity and aquaporin 4 expression in the trabecular meshwork, and increased tumor necrosis factor α and aquaporin 4 expression in the ciliary body. In the retina, cell density and insulin receptor expression decreased in the retinal ganglion cell layer upon S961 injection. Fundus photography revealed peripapillary atrophy with vascular dysregulation in the experimental group. These retinal changes were accompanied by upregulation of pro-inflammatory and pro-apoptotic genes, downregulation of anti-inflammatory, anti-apoptotic, and neurotrophic genes, as well as dysregulation of genes involved in insulin signaling. Optic nerve histology indicated microglial activation and changes in the expression of glial fibrillary acidic protein, tumor necrosis factor α, and aquaporin 4. Molecular pathway architecture of the retina revealed the three most significant pathways involved being inflammation/cell stress, insulin signaling, and extracellular matrix regulation relevant to neurodegeneration. There was also a multimodal crosstalk between insulin signaling derangement and inflammation-related genes. Taken together, our results indicate that blocking insulin receptor signaling in the central nervous system can lead to trabecular meshwork and ciliary body dysfunction, intraocular pressure elevation, as well as inflammation, glial activation, and apoptosis in the retina and optic nerve. Given that central insulin resistance may lead to neurodegenerative phenotype in the visual system, targeting insulin signaling may hold promise for vision disorders involving the retina and optic nerve.
Collapse
Affiliation(s)
- Muneeb A. Faiq
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India,Neuroimaging and Visual Science Laboratory, Department of Ophthalmology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY, USA,Medical Biotechnology Laboratory, Dr. B. R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi, India
| | - Trina Sengupta
- Dr. Baldev Singh Sleep Laboratory, Department of Physiology, All India Institute of Medical Sciences, New Delhi, India
| | - Madhu Nath
- Department of Ocular Pharmacology, Dr. Rajendra Prasad Center for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Thirumurthy Velpandian
- Department of Ocular Pharmacology, Dr. Rajendra Prasad Center for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Daman Saluja
- Medical Biotechnology Laboratory, Dr. B. R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi, India
| | - Rima Dada
- Laboratory for Molecular Reproduction and Genetics, Department of Anatomy, All India Institute of Medical Sciences, New Delhi, India
| | - Tanuj Dada
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India,Correspondence to: Tanuj Dada, ; Kevin C. Chan, .
| | - Kevin C. Chan
- Neuroimaging and Visual Science Laboratory, Department of Ophthalmology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY, USA,Correspondence to: Tanuj Dada, ; Kevin C. Chan, .
| |
Collapse
|
19
|
Van Hook MJ. Influences of Glaucoma on the Structure and Function of Synapses in the Visual System. Antioxid Redox Signal 2022; 37:842-861. [PMID: 35044228 PMCID: PMC9587776 DOI: 10.1089/ars.2021.0253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 12/31/2021] [Indexed: 11/12/2022]
Abstract
Significance: Glaucoma is an age-related neurodegenerative disorder of the visual system associated with sensitivity to intraocular pressure (IOP). It is the leading irreversible cause of vision loss worldwide, and vision loss results from damage and dysfunction of the retinal output neurons known as retinal ganglion cells (RGCs). Recent Advances: Elevated IOP and optic nerve injury triggers pruning of RGC dendrites, altered morphology of excitatory inputs from presynaptic bipolar cells, and disrupted RGC synaptic function. Less is known about RGC outputs, although evidence to date indicates that glaucoma is associated with altered mitochondrial and synaptic structure and function in RGC-projection targets in the brain. These early functional changes likely contribute to vision loss and might be a window into early diagnosis and treatment. Critical Issues: Glaucoma affects different RGC populations to varying extents and along distinct time courses. The influence of glaucoma on RGC synaptic function as well as the mechanisms underlying these effects remain to be determined. Since RGCs are an especially energetically demanding population of neurons, altered intracellular axon transport of mitochondria and mitochondrial function might contribute to RGC synaptic dysfunction in the retina and brain as well as RGC vulnerability in glaucoma. Future Directions: The mechanisms underlying differential RGC vulnerability remain to be determined. Moreover, the timing and mechanisms of RGCs synaptic dysfunction and degeneration will provide valuable insight into the disease process in glaucoma. Future work will be able to capitalize on these findings to better design diagnostic and therapeutic approaches to detect disease and prevent vision loss. Antioxid. Redox Signal. 37, 842-861.
Collapse
Affiliation(s)
- Matthew J. Van Hook
- Department of Ophthalmology & Visual Science and Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, Nebraska, USA
- Department of Cellular & Integrative Physiology, Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, Nebraska, USA
| |
Collapse
|
20
|
Johnson TV, Polo AD, Sahel JA, Schuman JS. Neuroprotection, Neuroenhancement, and Neuroregeneration of the Retina and Optic Nerve. OPHTHALMOLOGY SCIENCE 2022; 2:100216. [PMID: 36245765 PMCID: PMC9559091 DOI: 10.1016/j.xops.2022.100216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
21
|
Espinosa-Jiménez T, Busquets O, Cano A, Sánchez-López E, Verdaguer E, Parcerisas A, Olloquequi J, Auladell C, Folch J, Wahli W, Vázquez-Carrera M, Camins A, Ettcheto M. Peroxisomal Proliferator-Activated Receptor β/δ Deficiency Induces Cognitive Alterations. Front Pharmacol 2022; 13:902047. [PMID: 35899125 PMCID: PMC9310104 DOI: 10.3389/fphar.2022.902047] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 06/06/2022] [Indexed: 11/13/2022] Open
Abstract
Peroxisome proliferator-activated receptor β/δ (PPARβ/δ), the most PPAR abundant isotype in the central nervous system, is involved in microglial homeostasis and metabolism, whose disturbances have been demonstrated to play a key role in memory impairment. Although PPARβ/δ function is well-established in metabolism, its contribution to neuronal and specifically memory process is underexplored. Therefore, the aim of the study is to determine the role of PPARβ/δ in the neuropathological pathways involved in memory impairment and as to whether a risk factor implicated in memory loss such as obesity modulates neuropathological markers. To carry out this study, 6-month-old total knock-out for the Ppard gene male mice with C57BL/6X129/SV background (PPARβ/δ-/-) and wild-type (WT) littermates with the same genetic background were used. Animals were fed, after the weaning (at 21 days old), and throughout their growth, either conventional chow (CT) or a palmitic acid-enriched diet (HFD). Thus, four groups were defined: WT CT, WT HFD, PPARβ/δ-/- CT, and PPARβ/δ-/- HFD. Before sacrifice, novel object recognition test (NORT) and glucose and insulin tolerance tests were performed. After that, animals were sacrificed by intracardiac perfusion or cervical dislocation. Different techniques, such as GolgiStain kit or immunofluorescence, were used to evaluate the role of PPARβ/δ in memory dysfunction. Our results showed a decrease in dendritic spine density and synaptic markers in PPARβ/δ-/- mice, which were corroborated in the NORT. Likewise, our study demonstrated that the lack of PPARβ/δ receptor enhances gliosis in the hippocampus, contributing to astrocyte and microglial activation and to the increase in neuroinflammatory biomarkers. Additionally, alterations in the hippocampal insulin receptor pathway were found. Interestingly, while some of the disturbances caused by the lack of PPARβ/δ were not affected by feeding the HFD, others were exacerbated or required the combination of both factors. Taken together, the loss of PPARβ/δ-/- affects neuronal and synaptic structure, contributing to memory dysfunction, and they also present this receptor as a possible new target for the treatment of memory impairment.
Collapse
Affiliation(s)
- Triana Espinosa-Jiménez
- Department of Pharmacology, Toxicology and Therapeutic Chemistry, Faculty of Pharmacy and Food Sciences, University of Barcelona, Barcelona, Spain
- Biomedical Research Networking Centre in Neurodegenerative Diseases (CIBERNED), Madrid, Spain
- Institute of Neuroscience, University of Barcelona, Barcelona, Spain
| | - Oriol Busquets
- Dominick P. Purpura Department of Neurosciences, Albert Einstein College of Medicine, New York City, NY, United States
| | - Amanda Cano
- Biomedical Research Networking Centre in Neurodegenerative Diseases (CIBERNED), Madrid, Spain
- Institute of Nanoscience and Nanotechnology (IN2UB), University of Barcelona, Barcelona, Spain
- Department of Pharmacy, Pharmaceutical Technology and Physical Chemistry, Faculty of Pharmacy and Food Science, University of Barcelona, Barcelona, Spain
- Research Center and Memory Clinic, Fundació ACE Institut Català de Neurociències Aplicades—International University of Catalunya (UIC), Barcelona, Spain
| | - Elena Sánchez-López
- Biomedical Research Networking Centre in Neurodegenerative Diseases (CIBERNED), Madrid, Spain
- Institute of Nanoscience and Nanotechnology (IN2UB), University of Barcelona, Barcelona, Spain
- Department of Pharmacy, Pharmaceutical Technology and Physical Chemistry, Faculty of Pharmacy and Food Science, University of Barcelona, Barcelona, Spain
- Unit of Synthesis and Biomedical Applications of Peptides, IQAC-CSIC, Barcelona, Spain
| | - Ester Verdaguer
- Biomedical Research Networking Centre in Neurodegenerative Diseases (CIBERNED), Madrid, Spain
- Institute of Neuroscience, University of Barcelona, Barcelona, Spain
- Department of Cellular Biology, Physiology and Immunology, Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - Antoni Parcerisas
- Departament of Basic Sciences, Universitat Internacional de Catalunya (UIC), Sant Cugat del Vallès, Spain
| | - Jordi Olloquequi
- Department of Biochemistry and Physiology, Faculty of Pharmacy and Food Science, University of Barcelona, Barcelona, Spain
| | - Carme Auladell
- Biomedical Research Networking Centre in Neurodegenerative Diseases (CIBERNED), Madrid, Spain
- Institute of Neuroscience, University of Barcelona, Barcelona, Spain
- Department of Cellular Biology, Physiology and Immunology, Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - Jaume Folch
- Biomedical Research Networking Centre in Neurodegenerative Diseases (CIBERNED), Madrid, Spain
- Department of Biochemistry and Biotechnology, Faculty of Medicine and Life Science, University Rovira i Virgili, Reus, Spain
| | - Walter Wahli
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
- ToxAlim (Research Center in Food Toxicology), INRAE, Toulouse Cedex, France
| | - Manuel Vázquez-Carrera
- Department of Pharmacology, Toxicology and Therapeutic Chemistry, Faculty of Pharmacy and Food Sciences, University of Barcelona, Barcelona, Spain
- Institute of Biomedicine of the University of Barcelona (IBUB), University of Barcelona, Barcelona, Spain
- Spanish Biomedical Research Center in Diabetes and Associated Metabolic Diseases (CIBERDEM)-Instituto de Salud Carlos III, Madrid, Spain
| | - Antoni Camins
- Department of Pharmacology, Toxicology and Therapeutic Chemistry, Faculty of Pharmacy and Food Sciences, University of Barcelona, Barcelona, Spain
- Biomedical Research Networking Centre in Neurodegenerative Diseases (CIBERNED), Madrid, Spain
- Institute of Neuroscience, University of Barcelona, Barcelona, Spain
| | - Miren Ettcheto
- Department of Pharmacology, Toxicology and Therapeutic Chemistry, Faculty of Pharmacy and Food Sciences, University of Barcelona, Barcelona, Spain
- Biomedical Research Networking Centre in Neurodegenerative Diseases (CIBERNED), Madrid, Spain
- Institute of Neuroscience, University of Barcelona, Barcelona, Spain
- *Correspondence: Miren Ettcheto,
| |
Collapse
|
22
|
Chronic Chemogenetic Activation of the Superior Colliculus in Glaucomatous Mice: Local and Retrograde Molecular Signature. Cells 2022; 11:cells11111784. [PMID: 35681479 PMCID: PMC9179903 DOI: 10.3390/cells11111784] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 05/20/2022] [Accepted: 05/22/2022] [Indexed: 12/13/2022] Open
Abstract
One important facet of glaucoma pathophysiology is axonal damage, which ultimately disrupts the connection between the retina and its postsynaptic brain targets. The concurrent loss of retrograde support interferes with the functionality and survival of the retinal ganglion cells (RGCs). Previous research has shown that stimulation of neuronal activity in a primary retinal target area—i.e., the superior colliculus—promotes RGC survival in an acute mouse model of glaucoma. To build further on this observation, we applied repeated chemogenetics in the superior colliculus of a more chronic murine glaucoma model—i.e., the microbead occlusion model—and performed bulk RNA sequencing on collicular lysates and isolated RGCs. Our study revealed that chronic target stimulation upon glaucomatous injury phenocopies the a priori expected molecular response: growth factors were pinpointed as essential transcriptional regulators both in the locally stimulated tissue and in distant, unstimulated RGCs. Strikingly, and although the RGC transcriptome revealed a partial reversal of the glaucomatous signature and an enrichment of pro-survival signaling pathways, functional rescue of injured RGCs was not achieved. By postulating various explanations for the lack of RGC neuroprotection, we aim to warrant researchers and drug developers for the complexity of chronic neuromodulation and growth factor signaling.
Collapse
|
23
|
Boccuni I, Fairless R. Retinal Glutamate Neurotransmission: From Physiology to Pathophysiological Mechanisms of Retinal Ganglion Cell Degeneration. Life (Basel) 2022; 12:638. [PMID: 35629305 PMCID: PMC9147752 DOI: 10.3390/life12050638] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 04/22/2022] [Accepted: 04/22/2022] [Indexed: 12/12/2022] Open
Abstract
Glutamate neurotransmission and metabolism are finely modulated by the retinal network, where the efficient processing of visual information is shaped by the differential distribution and composition of glutamate receptors and transporters. However, disturbances in glutamate homeostasis can result in glutamate excitotoxicity, a major initiating factor of common neurodegenerative diseases. Within the retina, glutamate excitotoxicity can impair visual transmission by initiating degeneration of neuronal populations, including retinal ganglion cells (RGCs). The vulnerability of RGCs is observed not just as a result of retinal diseases but has also been ascribed to other common neurodegenerative and peripheral diseases. In this review, we describe the vulnerability of RGCs to glutamate excitotoxicity and the contribution of different glutamate receptors and transporters to this. In particular, we focus on the N-methyl-d-aspartate (NMDA) receptor as the major effector of glutamate-induced mechanisms of neurodegeneration, including impairment of calcium homeostasis, changes in gene expression and signalling, and mitochondrial dysfunction, as well as the role of endoplasmic reticular stress. Due to recent developments in the search for modulators of NMDA receptor signalling, novel neuroprotective strategies may be on the horizon.
Collapse
Affiliation(s)
- Isabella Boccuni
- Institute for Physiology and Pathophysiology, Heidelberg University, 69120 Heidelberg, Germany
- Department of Neurology, University Clinic Heidelberg, 69120 Heidelberg, Germany;
| | - Richard Fairless
- Department of Neurology, University Clinic Heidelberg, 69120 Heidelberg, Germany;
- Clinical Cooperation Unit (CCU) Neurooncology, German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
| |
Collapse
|
24
|
Insulin receptor activation by proinsulin preserves synapses and vision in retinitis pigmentosa. Cell Death Dis 2022; 13:383. [PMID: 35444190 PMCID: PMC9021205 DOI: 10.1038/s41419-022-04839-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 04/04/2022] [Accepted: 04/05/2022] [Indexed: 11/23/2022]
Abstract
Synaptic loss, neuronal death, and circuit remodeling are common features of central nervous system neurodegenerative disorders. Retinitis pigmentosa (RP), the leading cause of inherited blindness, is a group of retinal dystrophies characterized by photoreceptor dysfunction and death. The insulin receptor, a key controller of metabolism, also regulates neuronal survival and synaptic formation, maintenance, and activity. Indeed, deficient insulin receptor signaling has been implicated in several brain neurodegenerative pathologies. We present evidence linking impaired insulin receptor signaling with RP. We describe a selective decrease in the levels of the insulin receptor and its downstream effector phospho-S6 in retinal horizontal cell terminals in the rd10 mouse model of RP, as well as aberrant synapses between rod photoreceptors and the postsynaptic terminals of horizontal and bipolar cells. A gene therapy strategy to induce sustained proinsulin, the insulin precursor, production restored retinal insulin receptor signaling, by increasing S6 phosphorylation, without peripheral metabolic consequences. Moreover, proinsulin preserved photoreceptor synaptic connectivity and prolonged visual function in electroretinogram and optomotor tests. These findings point to a disease-modifying role of insulin receptor and support the therapeutic potential of proinsulin in retinitis pigmentosa.
Collapse
|
25
|
Li MX, Weng JW, Ho ES, Chow SF, Tsang CK. Brain delivering RNA-based therapeutic strategies by targeting mTOR pathway for axon regeneration after central nervous system injury. Neural Regen Res 2022; 17:2157-2165. [PMID: 35259823 PMCID: PMC9083176 DOI: 10.4103/1673-5374.335830] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Injuries to the central nervous system (CNS) such as stroke, brain, and spinal cord trauma often result in permanent disabilities because adult CNS neurons only exhibit limited axon regeneration. The brain has a surprising intrinsic capability of recovering itself after injury. However, the hostile extrinsic microenvironment significantly hinders axon regeneration. Recent advances have indicated that the inactivation of intrinsic regenerative pathways plays a pivotal role in the failure of most adult CNS neuronal regeneration. Particularly, substantial evidence has convincingly demonstrated that the mechanistic target of rapamycin (mTOR) signaling is one of the most crucial intrinsic regenerative pathways that drive axonal regeneration and sprouting in various CNS injuries. In this review, we will discuss the recent findings and highlight the critical roles of mTOR pathway in axon regeneration in different types of CNS injury. Importantly, we will demonstrate that the reactivation of this regenerative pathway can be achieved by blocking the key mTOR signaling components such as phosphatase and tensin homolog (PTEN). Given that multiple mTOR signaling components are endogenous inhibitory factors of this pathway, we will discuss the promising potential of RNA-based therapeutics which are particularly suitable for this purpose, and the fact that they have attracted substantial attention recently after the success of coronavirus disease 2019 vaccination. To specifically tackle the blood-brain barrier issue, we will review the current technology to deliver these RNA therapeutics into the brain with a focus on nanoparticle technology. We will propose the clinical application of these RNA-mediated therapies in combination with the brain-targeted drug delivery approach against mTOR signaling components as an effective and feasible therapeutic strategy aiming to enhance axonal regeneration for functional recovery after CNS injury.
Collapse
Affiliation(s)
- Ming-Xi Li
- Clinical Neuroscience Institute, The First Affiliated Hospital of Jinan University, Guangzhou, Guangdong Province, China
| | - Jing-Wen Weng
- Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Eric S Ho
- Department of Biology and Department of Computer Science, Lafayette College, Easton, PA, USA
| | - Shing Fung Chow
- Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Chi Kwan Tsang
- Clinical Neuroscience Institute, The First Affiliated Hospital of Jinan University, Guangzhou, Guangdong Province, China
| |
Collapse
|
26
|
Mouhammad ZA, Vohra R, Horwitz A, Thein AS, Rovelt J, Cvenkel B, Williams PA, Azuara-Blanco A, Kolko M. Glucagon-Like Peptide 1 Receptor Agonists – Potential Game Changers in the Treatment of Glaucoma? Front Neurosci 2022; 16:824054. [PMID: 35264926 PMCID: PMC8899005 DOI: 10.3389/fnins.2022.824054] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Accepted: 01/10/2022] [Indexed: 12/22/2022] Open
Abstract
Glaucoma is a common ocular neurodegenerative disease characterized by the progressive loss of retinal ganglion cells and their axons. It is the most common cause of irreversible blindness. With an increasing number of glaucoma patients and disease progression despite treatment, it is paramount to develop new and effective therapeutics. Emerging new candidates are the receptor agonists of the incretin hormone glucagon-like-peptide-1 (GLP-1), originally used for the treatment of diabetes. GLP-1 receptor (GLP-1R) agonists have shown neuroprotective effects in preclinical and clinical studies on neurodegenerative diseases in both the brain (e.g., Alzheimer’s disease, Parkinson’s disease, stroke and diabetic neuropathy) and the eye (e.g., diabetic retinopathy and AMD). However, there are currently very few studies investigating the protective effects of GLP-1R agonists in the treatment of specifically glaucoma. Based on a literature search on PubMed, the Cochrane Library, and ClinicalTrials.gov, this review aims to summarize current clinical literature on GLP-1 receptor agonists in the treatment of neurodegenerative diseases to elucidate their potential in future anti-glaucomatous treatment strategies.
Collapse
Affiliation(s)
- Zaynab Ahmad Mouhammad
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Rupali Vohra
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
- Department of Veterinary and Animal Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Anna Horwitz
- Department of Ophthalmology, Copenhagen University Hospital, Rigshospitalet, Glostrup, Denmark
| | - Anna-Sophie Thein
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Jens Rovelt
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Barbara Cvenkel
- Department of Ophthalmology, University Medical Centre Ljubljana, Ljubljana, Slovenia
- Medical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Pete A. Williams
- Division of Eye and Vision, Department of Clinical Neuroscience, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden
| | | | - Miriam Kolko
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
- Department of Ophthalmology, Copenhagen University Hospital, Rigshospitalet, Glostrup, Denmark
- *Correspondence: Miriam Kolko,
| |
Collapse
|
27
|
Systemic Treatment with Pioglitazone Reverses Vision Loss in Preclinical Glaucoma Models. Biomolecules 2022; 12:biom12020281. [PMID: 35204782 PMCID: PMC8961625 DOI: 10.3390/biom12020281] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 02/03/2022] [Accepted: 02/08/2022] [Indexed: 02/04/2023] Open
Abstract
Neuroinflammation significantly contributes to the pathophysiology of several neurodegenerative diseases. This is also the case in glaucoma and may be a reason why many patients suffer from progressive vision loss despite maximal reduction in intraocular pressure. Pioglitazone is an agonist of the peroxisome proliferator-activated receptor gamma (PPARγ) whose pleiotrophic activities include modulation of cellular energy metabolism and reduction in inflammation. In this study we employed the DBA2/J mouse model of glaucoma with chronically elevated intraocular pressure to investigate whether oral low-dose pioglitazone treatment preserves retinal ganglion cell (RGC) survival. We then used an inducible glaucoma model in C57BL/6J mice to determine visual function, pattern electroretinographs, and tracking of optokinetic reflex. Our findings demonstrate that pioglitazone treatment does significantly protect RGCs and prevents axonal degeneration in the glaucomatous retina. Furthermore, treatment preserves and partially reverses vision loss in spite of continuously elevated intraocular pressure. These data suggest that pioglitazone may provide treatment benefits for those glaucoma patients experiencing continued vision loss.
Collapse
|
28
|
IRS1 expression in hippocampus is age-dependent and is required for mature spine maintenance and neuritogenesis. Mol Cell Neurosci 2021; 118:103693. [PMID: 34942345 DOI: 10.1016/j.mcn.2021.103693] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 12/03/2021] [Accepted: 12/06/2021] [Indexed: 11/21/2022] Open
Abstract
Insulin and insulin-like growth factor type I (IGF-1) play prominent roles in brain activity throughout the lifespan. Insulin/IGF1 signaling starts with the activation of the intracellular insulin receptor substrates (IRS). In this work, we performed a comparative study of IRS1 and IRS2, together with the IGF1 (IGF1R) and insulin (IR) receptor expression in the hippocampus and prefrontal cortex during development. We found that IRS1 and IRS2 expression is prominent during development and declines in the aged hippocampus, contrary to IR, which increases in adulthood and aging. In contrast, IGF1R expression is unaffected by age. Expression patterns are similar in the prefrontal cortex. Neurite development occurs postnatally in the rodent hippocampus and cortex, and it declines in the mature and aged brain and is influenced by trophic factors. In our previous work, we demonstrated that knockdown of IRS1 by shRNA impairs learning and reduces synaptic plasticity in a rat model, as measured by synaptophysin puncta in axons. In this study, we report that shIRS1 alters spine maturation in adult hilar hippocampal neurons. Lastly, to understand the role of IRS1 in neuronal neurite tree, we transfect shIRS1 into primary neuronal cultures and observed that shIRS1 reduced neurite branching and neurite length. Our results demonstrate that IRS1/2 and insulin/IGF1 receptors display different age-dependent expression profiles and that IRS1 is required for spine maturation, demonstrating a novel role for IRS1 in synaptic plasticity.
Collapse
|
29
|
Jassim AH, Fan Y, Pappenhagen N, Nsiah NY, Inman DM. Oxidative Stress and Hypoxia Modify Mitochondrial Homeostasis During Glaucoma. Antioxid Redox Signal 2021; 35:1341-1357. [PMID: 33736457 PMCID: PMC8817702 DOI: 10.1089/ars.2020.8180] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Aims: Cellular response to hypoxia can include transition from respiration to glycolysis via upregulation of glycolytic enzymes and transporters, as well as mitophagy induction to eliminate surplus mitochondria. Our purpose was to evaluate the impact of hypoxia-inducible factor-1α (HIF-1α) stabilization on mitochondrial homeostasis and oxidative stress in a chronic model of glaucoma. Results: Retina and optic nerve (ON) were evaluated from young and aged DBA/2J (D2) glaucoma model mice and the control strain, the DBA/2-Gpnmb+. Hypoxic retinal ganglion cells (RGCs) were observed in young and aged D2 retina, with a significant increase in HIF-1α protein in the aged D2 retina. Reactive oxygen species observed in young D2 retina and ON were followed by significant decreases in antioxidant capacity in aged D2 retina and ON. HIF-1α targets such as neuron-specific glucose transporter-3 and lactate dehydrogenase were decreased or unchanged, respectively, in aged D2 retina despite an increased hypoxia response in RGCs. Mitochondrial mass was decreased in aged D2 retina concomitant with decreased mitochondrially encoded electron transport chain transcripts despite a stable nuclear-encoded TFAM (mitochondrial transcription factor), suggesting a breakdown in the nuclear-mitochondrial communication. Decreased mitophagy-associated proteins p62 and Rheb were observed in aged D2 retina, although p62 was significantly increased in the aged D2 ON. Innovation and Conclusion: The increased reactive oxygen species concomitant with HIF-1α upregulation despite reduced glucose transporters, mis-match of nuclear- and mitochondrial-encoded transcripts, and signs of reduced mitophagy suggest that retinas from D2 mice with chronic intraocular pressure elevation transition to pseudohypoxia without consistent metabolic reprogramming before significant RGC loss. Antioxid. Redox Signal. 35, 1341-1357.
Collapse
Affiliation(s)
- Assraa Hassan Jassim
- Department of Pharmaceutical Sciences, Northeast Ohio Medical University, Rootstown, Ohio, USA
| | - Yan Fan
- Department of Pharmaceutical Sciences, North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas, USA
| | - Nathaniel Pappenhagen
- Department of Pharmaceutical Sciences, North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas, USA
- Kent State University School of Biomedical Sciences, Kent, Ohio, USA
| | - Nana Yaa Nsiah
- Department of Pharmaceutical Sciences, North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas, USA
| | - Denise M. Inman
- Department of Pharmaceutical Sciences, North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas, USA
- Address correspondence to: Dr. Denise M. Inman, Department of Pharmaceutical Sciences, North Texas Eye Research Institute, University of North Texas Health Science Center, 3500 Camp Bowie Boulevard, Fort Worth, TX 76107, USA
| |
Collapse
|
30
|
Fague L, Liu YA, Marsh-Armstrong N. The basic science of optic nerve regeneration. ANNALS OF TRANSLATIONAL MEDICINE 2021; 9:1276. [PMID: 34532413 PMCID: PMC8421956 DOI: 10.21037/atm-20-5351] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 01/15/2021] [Indexed: 12/25/2022]
Abstract
Diverse insults to the optic nerve result in partial to total vision loss as the axons of retinal ganglion cells are destroyed. In glaucoma, axons are injured at the optic nerve head; in other optic neuropathies, axons can be damaged along the entire visual pathway. In all cases, as mammals cannot regenerate injured central nervous system cells, once the axons are lost, vision loss is irreversible. However, much has been learned about how retinal ganglion cells respond to axon injuries, and many of these crucial discoveries offer hope for future regenerative therapies. Here we review the current understanding regarding the temporal progression of axonal degeneration. We summarize known survival and regenerative mechanisms in mammals, including specific signaling pathways, key transcription factors, and reprogramming genes. We cover mechanisms intrinsic to retinal ganglion cells as well as their interactions with myeloid and glial cell populations in the retina and optic nerve that affect survival and regeneration. Finally, we highlight some non-mammalian species that are able to regenerate their retinal ganglion cell axons after injury, as understanding these successful regenerative responses may be essential to the rational design of future clinical interventions to regrow the optic nerve. In the end, a combination of many different molecular and cellular interventions will likely be the only way to achieve functional recovery of vision and restore quality of life to millions of patients around the world.
Collapse
Affiliation(s)
- Lindsay Fague
- UC Davis Eye Center, Department of Ophthalmology & Vision Science, University of California, Davis, Sacramento, CA, USA
| | - Yin Allison Liu
- UC Davis Eye Center, Department of Ophthalmology & Vision Science, University of California, Davis, Sacramento, CA, USA
| | - Nicholas Marsh-Armstrong
- UC Davis Eye Center, Department of Ophthalmology & Vision Science, University of California, Davis, Sacramento, CA, USA
| |
Collapse
|
31
|
Storgaard L, Tran TL, Freiberg JC, Hauser AS, Kolko M. Glaucoma Clinical Research: Trends in Treatment Strategies and Drug Development. Front Med (Lausanne) 2021; 8:733080. [PMID: 34589504 PMCID: PMC8473801 DOI: 10.3389/fmed.2021.733080] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 08/11/2021] [Indexed: 01/30/2023] Open
Abstract
Purpose: To investigate the trends and progresses in glaucoma research by searching two major clinical trial registries; clinicaltrials.gov, and Australianclinicaltrials.gov.au. Methods: All clinical trials with glaucoma covered by Clinicaltrials.gov, and Australianclinicaltrials.gov.au starting the study before 1 January 2021 were included. Trials evaluating glaucoma treatment were separated from non-treatment trials and divided into three major categories: "laser treatment," "surgical treatment," and "medical treatment." In the category of "medical treatment," new compounds and their individual targets were identified and subcategorized according to treatment strategy; intraocular pressure (IOP)-lowering, neuroprotective or vascular. The phase transition success rates were calculated. Results: One-thousand five hundred and thirty-seven trials were identified. Sixty-three percent (n = 971) evaluated glaucoma treatment, of which medical treatment accounted for the largest proportion (53%). The majority of medical trials evaluated IOP-lowering compounds, while trials with neuroprotective or vascular compounds accounted for only 5 and 3%, respectively. Eighty-eight new compounds were identified. Phase I, II, and III transition success rates were 63, 26, and 47%, respectively. Conclusion: The number of clinical trials in glaucoma research has increased significantly over the last 30 years. Among the most recently evaluated compounds, all three main treatment strategies were represented, but clinical trials in neuroprotection and vascular modalities are still sparse. In addition to traditional medicines, dietary supplements and growth factors are assessed for a potential anti-glaucomatous effect. Phase II and III success rates were below previously reported success rates for all diseases and ophthalmology in general. A stricter phenotyping of patients can improve the success rates in glaucoma and ophthalmological research and gain a better understanding of responders and non-responders.
Collapse
Affiliation(s)
- Line Storgaard
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Thuy Linh Tran
- Department of Ophthalmology, Copenhagen University Hospital, Rigshospitalet-Glostrup, Copenhagen, Denmark
| | | | - Alexander S. Hauser
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Miriam Kolko
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
- Department of Ophthalmology, Copenhagen University Hospital, Rigshospitalet-Glostrup, Copenhagen, Denmark
| |
Collapse
|
32
|
The Pathogenesis and Therapeutic Approaches of Diabetic Neuropathy in the Retina. Int J Mol Sci 2021; 22:ijms22169050. [PMID: 34445756 PMCID: PMC8396448 DOI: 10.3390/ijms22169050] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 08/19/2021] [Accepted: 08/19/2021] [Indexed: 02/07/2023] Open
Abstract
Diabetic retinopathy is a major retinal disease and a leading cause of blindness in the world. Diabetic retinopathy is a neurovascular disease that is associated with disturbances of the interdependent relationship of cells composed of the neurovascular units, i.e., neurons, glial cells, and vascular cells. An impairment of these neurovascular units causes both neuronal and vascular abnormalities in diabetic retinopathy. More specifically, neuronal abnormalities including neuronal cell death and axon degeneration are irreversible changes that are directly related to the vision reduction in diabetic patients. Thus, establishment of neuroprotective and regenerative therapies for diabetic neuropathy in the retina is an emergent task for preventing the blindness of patients with diabetic retinopathy. This review focuses on the pathogenesis of the neuronal abnormalities in diabetic retina including glial abnormalities, neuronal cell death, and axon degeneration. The possible molecular cell death pathways and intrinsic survival and regenerative pathways are also described. In addition, therapeutic approaches for diabetic neuropathy in the retina both in vitro and in vivo are presented. This review should be helpful for providing clues to overcome the barriers for establishing neuroprotection and regeneration of diabetic neuropathy in the retina.
Collapse
|
33
|
Comparing Automated Morphology Quantification Software on Dendrites of Uninjured and Injured Drosophila Neurons. Neuroinformatics 2021; 19:703-717. [PMID: 34342808 PMCID: PMC8566419 DOI: 10.1007/s12021-021-09532-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/10/2021] [Indexed: 10/28/2022]
Abstract
Dendrites shape inputs and integration of depolarization that controls neuronal activity in the nervous system. Neuron pathologies can damage dendrite architecture and cause abnormalities in morphologies after injury. Dendrite regeneration can be quantified by various parameters, including total dendrite length and number of dendrite branches using manual or automated image analysis approaches. However, manual quantification is tedious and time consuming and automated approaches are often trained using wildtype neurons, making them poorly suited for analysis of genetically manipulated or injured dendrite arbors. In this study, we tested how well automated image analysis software performed on class IV Drosophila neurons, which have several hundred individual dendrite branches. We applied each software to automatically quantify features of uninjured neurons and neurons that regenerated new dendrites after injury. Regenerated arbors exhibit defects across multiple features of dendrite morphology, which makes them challenging for automated pipelines to analyze. We compared the performances of three automated pipelines against manual quantification using Simple Neurite Tracer in ImageJ: one that is commercially available (Imaris) and two developed by independent research groups (DeTerm and Tireless Tracing Genie). Out of the three software tested, we determined that Imaris is the most efficient at reconstructing dendrite architecture, but does not accurately measure total dendrite length even after intensive manual editing. Imaris outperforms both DeTerm and Tireless Tracing Genie for counting dendrite branches, and is better able to recreate previous conclusions from this same dataset. This thorough comparison of strengths and weaknesses of each software demonstrates their utility for analyzing regenerated neuron phenotypes in future studies.
Collapse
|
34
|
Beckers A, Vanhunsel S, Van Dyck A, Bergmans S, Masin L, Moons L. Injury-induced Autophagy Delays Axonal Regeneration after Optic Nerve Damage in Adult Zebrafish. Neuroscience 2021; 470:52-69. [PMID: 34280491 DOI: 10.1016/j.neuroscience.2021.07.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 06/18/2021] [Accepted: 07/09/2021] [Indexed: 12/15/2022]
Abstract
Optic neuropathies comprise a group of disorders in which the axons of retinal ganglion cells (RGCs), the retinal projection neurons conveying visual information to the brain, are damaged. This results in visual impairment or even blindness, which is irreversible as adult mammals lack the capacity to repair or replace injured or lost neurons. Despite intensive research, no efficient treatment to induce axonal regeneration in the central nervous system (CNS) is available yet. Autophagy, the cellular recycling response, was shown repeatedly to be elevated in animal models of optic nerve injury, and both beneficial and detrimental effects have been reported. In this study, we subjected spontaneously regenerating adult zebrafish to optic nerve damage (ONC) and revealed that autophagy is enhanced after optic nerve damage in zebrafish, both in RGC axons and somas, as well as in macroglial cells of the retina, the optic nerve and the visual target areas in the brain. Interestingly, the pattern of the autophagic response in the axons followed the spatiotemporal window of axonal regrowth, which suggests that autophagy is ongoing at the growth cones. Pharmacological inhibition of the recycling pathway resulted in accelerated RGC target reinnervation, possibly linked to increased mechanistic target of rapamycin (mTOR) activity, known to stimulate axonal regrowth. Taken together, these intriguing findings underline that further research is warranted to decipher if modulation of autophagy could be an effective therapeutic method to induce CNS regeneration.
Collapse
Affiliation(s)
- An Beckers
- Neural Circuit Development and Regeneration Research Group, Animal Physiology and Neurobiology Section, Department of Biology, KU Leuven, 3000 Leuven, Belgium
| | - Sophie Vanhunsel
- Neural Circuit Development and Regeneration Research Group, Animal Physiology and Neurobiology Section, Department of Biology, KU Leuven, 3000 Leuven, Belgium
| | - Annelies Van Dyck
- Neural Circuit Development and Regeneration Research Group, Animal Physiology and Neurobiology Section, Department of Biology, KU Leuven, 3000 Leuven, Belgium
| | - Steven Bergmans
- Neural Circuit Development and Regeneration Research Group, Animal Physiology and Neurobiology Section, Department of Biology, KU Leuven, 3000 Leuven, Belgium
| | - Luca Masin
- Neural Circuit Development and Regeneration Research Group, Animal Physiology and Neurobiology Section, Department of Biology, KU Leuven, 3000 Leuven, Belgium
| | - Lieve Moons
- Neural Circuit Development and Regeneration Research Group, Animal Physiology and Neurobiology Section, Department of Biology, KU Leuven, 3000 Leuven, Belgium; Leuven Brain Institute, 3000 Leuven, Belgium.
| |
Collapse
|
35
|
Vidal-Villegas B, Di Pierdomenico J, Gallego-Ortega A, Galindo-Romero C, Martínez-de-la-Casa JM, García-Feijoo J, Villegas-Pérez MP, Vidal-Sanz M. Systemic treatment with 7,8-Dihydroxiflavone activates TtkB and affords protection of two different retinal ganglion cell populations against axotomy in adult rats. Exp Eye Res 2021; 210:108694. [PMID: 34245756 DOI: 10.1016/j.exer.2021.108694] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 05/26/2021] [Accepted: 07/01/2021] [Indexed: 12/25/2022]
Abstract
PURPOSE To analyze responses of different RGC populations to left intraorbital optic nerve transection (IONT) and intraperitoneal (i.p.) treatment with 7,8-Dihydroxyflavone (DHF), a potent selective TrkB agonist. METHODS Adult albino Sprague-Dawley rats received, following IONT, daily i.p. injections of vehicle (1%DMSO in 0.9%NaCl) or DHF. Group-1 (n = 58) assessed at 7days (d) the optimal DHF amount (1-25 mg/kg). Group-2, using freshly dissected naïve or treated retinas (n = 28), investigated if DHF treatment was associated with TrkB activation using Western-blotting at 1, 3 or 7d. Group-3 (n = 98) explored persistence of protection and was analyzed at survival intervals from 7 to 60d after IONT. Groups 2-3 received daily i.p. vehicle or DHF (5 mg/kg). Retinal wholemounts were immunolabelled for Brn3a and melanopsin to identify Brn3a+RGCs and m+RGCs, respectively. RESULTS Optimal neuroprotection was achieved with 5 mg/kg DHF and resulted in TrkB phosphorylation. The percentage of surviving Brn3a+RGCs in vehicle treated rats was 60, 28, 18, 13, 12 or 8% of the original value at 7, 10, 14, 21, 30 or 60d, respectively, while in DHF treated retinas was 94, 70, 64, 17, 10 or 9% at the same time intervals. The percentages of m+RGCs diminished by 7d-13%, and recovered by 14d-38% in vehicle-treated and to 48% in DHF-treated retinas, without further variations. CONCLUSIONS DHF neuroprotects Brn3a + RGCs and m + RGCs; its protective effects for Brn3a+RGCs are maximal at 7 days but still significant at 21d, whereas for m+RGCs neuroprotection was significant at 14d and permanent.
Collapse
Affiliation(s)
- Beatriz Vidal-Villegas
- Servicio de Oftalmología, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), 28040 Madrid, Spain; Departamento de Oftalmología, Universidad de Murcia e Instituto Murciano de Investigación Biosanitaria (IMIB) Virgen de la Arrixaca. Campus de CC de la Salud, 30120, El Palmar, Murcia, Spain
| | - Johnny Di Pierdomenico
- Departamento de Oftalmología, Universidad de Murcia e Instituto Murciano de Investigación Biosanitaria (IMIB) Virgen de la Arrixaca. Campus de CC de la Salud, 30120, El Palmar, Murcia, Spain
| | - Alejandro Gallego-Ortega
- Departamento de Oftalmología, Universidad de Murcia e Instituto Murciano de Investigación Biosanitaria (IMIB) Virgen de la Arrixaca. Campus de CC de la Salud, 30120, El Palmar, Murcia, Spain
| | - Caridad Galindo-Romero
- Departamento de Oftalmología, Universidad de Murcia e Instituto Murciano de Investigación Biosanitaria (IMIB) Virgen de la Arrixaca. Campus de CC de la Salud, 30120, El Palmar, Murcia, Spain
| | - Jose M Martínez-de-la-Casa
- Servicio de Oftalmología, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), 28040 Madrid, Spain
| | - Julian García-Feijoo
- Servicio de Oftalmología, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), 28040 Madrid, Spain
| | - María P Villegas-Pérez
- Servicio de Oftalmología, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), 28040 Madrid, Spain; Departamento de Oftalmología, Universidad de Murcia e Instituto Murciano de Investigación Biosanitaria (IMIB) Virgen de la Arrixaca. Campus de CC de la Salud, 30120, El Palmar, Murcia, Spain
| | - Manuel Vidal-Sanz
- Departamento de Oftalmología, Universidad de Murcia e Instituto Murciano de Investigación Biosanitaria (IMIB) Virgen de la Arrixaca. Campus de CC de la Salud, 30120, El Palmar, Murcia, Spain.
| |
Collapse
|
36
|
Belforte N, Agostinone J, Alarcon-Martinez L, Villafranca-Baughman D, Dotigny F, Cueva Vargas JL, Di Polo A. AMPK hyperactivation promotes dendrite retraction, synaptic loss, and neuronal dysfunction in glaucoma. Mol Neurodegener 2021; 16:43. [PMID: 34187514 PMCID: PMC8243567 DOI: 10.1186/s13024-021-00466-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 06/09/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The maintenance of complex dendritic arbors and synaptic transmission are processes that require a substantial amount of energy. Bioenergetic decline is a prominent feature of chronic neurodegenerative diseases, yet the signaling mechanisms that link energy stress with neuronal dysfunction are poorly understood. Recent work has implicated energy deficits in glaucoma, and retinal ganglion cell (RGC) dendritic pathology and synapse disassembly are key features of ocular hypertension damage. RESULTS We show that adenosine monophosphate-activated protein kinase (AMPK), a conserved energy biosensor, is strongly activated in RGC from mice with ocular hypertension and patients with primary open angle glaucoma. Our data demonstrate that AMPK triggers RGC dendrite retraction and synapse elimination. We show that the harmful effect of AMPK is exerted through inhibition of the mammalian target of rapamycin complex 1 (mTORC1). Attenuation of AMPK activity restores mTORC1 function and rescues dendrites and synaptic contacts. Strikingly, AMPK depletion promotes recovery of light-evoked retinal responses, improves axonal transport, and extends RGC survival. CONCLUSIONS This study identifies AMPK as a critical nexus between bioenergetic decline and RGC dysfunction during pressure-induced stress, and highlights the importance of targeting energy homeostasis in glaucoma and other neurodegenerative diseases.
Collapse
Affiliation(s)
- Nicolas Belforte
- Department of Neuroscience, Université de Montréal, Succursale centre-ville 6128, Montréal, Québec, H3C 3J7, Canada.,Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900 Saint Denis Street, Montréal, Québec, H2X 0A9, Canada
| | - Jessica Agostinone
- Department of Neuroscience, Université de Montréal, Succursale centre-ville 6128, Montréal, Québec, H3C 3J7, Canada.,Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900 Saint Denis Street, Montréal, Québec, H2X 0A9, Canada
| | - Luis Alarcon-Martinez
- Department of Neuroscience, Université de Montréal, Succursale centre-ville 6128, Montréal, Québec, H3C 3J7, Canada.,Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900 Saint Denis Street, Montréal, Québec, H2X 0A9, Canada
| | - Deborah Villafranca-Baughman
- Department of Neuroscience, Université de Montréal, Succursale centre-ville 6128, Montréal, Québec, H3C 3J7, Canada.,Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900 Saint Denis Street, Montréal, Québec, H2X 0A9, Canada
| | - Florence Dotigny
- Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900 Saint Denis Street, Montréal, Québec, H2X 0A9, Canada
| | - Jorge L Cueva Vargas
- Department of Neuroscience, Université de Montréal, Succursale centre-ville 6128, Montréal, Québec, H3C 3J7, Canada.,Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900 Saint Denis Street, Montréal, Québec, H2X 0A9, Canada
| | - Adriana Di Polo
- Department of Neuroscience, Université de Montréal, Succursale centre-ville 6128, Montréal, Québec, H3C 3J7, Canada. .,Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900 Saint Denis Street, Montréal, Québec, H2X 0A9, Canada.
| |
Collapse
|
37
|
Muench NA, Patel S, Maes ME, Donahue RJ, Ikeda A, Nickells RW. The Influence of Mitochondrial Dynamics and Function on Retinal Ganglion Cell Susceptibility in Optic Nerve Disease. Cells 2021; 10:cells10071593. [PMID: 34201955 PMCID: PMC8306483 DOI: 10.3390/cells10071593] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 06/15/2021] [Accepted: 06/17/2021] [Indexed: 12/30/2022] Open
Abstract
The important roles of mitochondrial function and dysfunction in the process of neurodegeneration are widely acknowledged. Retinal ganglion cells (RGCs) appear to be a highly vulnerable neuronal cell type in the central nervous system with respect to mitochondrial dysfunction but the actual reasons for this are still incompletely understood. These cells have a unique circumstance where unmyelinated axons must bend nearly 90° to exit the eye and then cross a translaminar pressure gradient before becoming myelinated in the optic nerve. This region, the optic nerve head, contains some of the highest density of mitochondria present in these cells. Glaucoma represents a perfect storm of events occurring at this location, with a combination of changes in the translaminar pressure gradient and reassignment of the metabolic support functions of supporting glia, which appears to apply increased metabolic stress to the RGC axons leading to a failure of axonal transport mechanisms. However, RGCs themselves are also extremely sensitive to genetic mutations, particularly in genes affecting mitochondrial dynamics and mitochondrial clearance. These mutations, which systemically affect the mitochondria in every cell, often lead to an optic neuropathy as the sole pathologic defect in affected patients. This review summarizes knowledge of mitochondrial structure and function, the known energy demands of neurons in general, and places these in the context of normal and pathological characteristics of mitochondria attributed to RGCs.
Collapse
Affiliation(s)
- Nicole A. Muench
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI 53706, USA; (N.A.M.); (S.P.); (R.J.D.)
| | - Sonia Patel
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI 53706, USA; (N.A.M.); (S.P.); (R.J.D.)
| | - Margaret E. Maes
- Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria;
| | - Ryan J. Donahue
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI 53706, USA; (N.A.M.); (S.P.); (R.J.D.)
- Boston Children’s Hospital, Harvard Medical School, Harvard University, Boston, MA 02115, USA
| | - Akihiro Ikeda
- Department of Medical Genetics, University of Wisconsin-Madison, Madison, WI 53706, USA;
- McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Robert W. Nickells
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI 53706, USA; (N.A.M.); (S.P.); (R.J.D.)
- McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI 53705, USA
- Correspondence:
| |
Collapse
|
38
|
Retinal Ganglion Cell Transplantation: Approaches for Overcoming Challenges to Functional Integration. Cells 2021; 10:cells10061426. [PMID: 34200991 PMCID: PMC8228580 DOI: 10.3390/cells10061426] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 06/01/2021] [Accepted: 06/03/2021] [Indexed: 02/07/2023] Open
Abstract
As part of the central nervous system, mammalian retinal ganglion cells (RGCs) lack significant regenerative capacity. Glaucoma causes progressive and irreversible vision loss by damaging RGCs and their axons, which compose the optic nerve. To functionally restore vision, lost RGCs must be replaced. Despite tremendous advancements in experimental models of optic neuropathy that have elucidated pathways to induce endogenous RGC neuroprotection and axon regeneration, obstacles to achieving functional visual recovery through exogenous RGC transplantation remain. Key challenges include poor graft survival, low donor neuron localization to the host retina, and inadequate dendritogenesis and synaptogenesis with afferent amacrine and bipolar cells. In this review, we summarize the current state of experimental RGC transplantation, and we propose a set of standard approaches to quantifying and reporting experimental outcomes in order to guide a collective effort to advance the field toward functional RGC replacement and optic nerve regeneration.
Collapse
|
39
|
Wang J, Struebing FL, Geisert EE. Commonalities of optic nerve injury and glaucoma-induced neurodegeneration: Insights from transcriptome-wide studies. Exp Eye Res 2021; 207:108571. [PMID: 33844961 PMCID: PMC9890784 DOI: 10.1016/j.exer.2021.108571] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 03/28/2021] [Accepted: 04/02/2021] [Indexed: 02/03/2023]
Abstract
Glaucoma is a collection of diseases that lead to an irreversible vision loss due to damage of retinal ganglion cells (RGCs). Although the underlying events leading to RGC death are not fully understood, recent research efforts are beginning to define the genetic changes that play a critical role in the initiation and progression of glaucomatous injury and RGC death. Several genetic and experimental animal models have been developed to mimic glaucomatous neurodegeneration. These models differ in many respects but all result in the loss of RGCs. Assessing transcriptional changes across different models could provide a more complete perspective on the molecular drivers of RGC degeneration. For the past several decades, changes in the retinal transcriptome during neurodegeneration process were defined using microarray methods, RNA sequencing and now single cell RNA sequencing. It is understood that these methods have strengths and weaknesses due to technical differences and variations in the analytical tools used. In this review, we focus on the use of transcriptome-wide expression profiling of the changes occurring as RGCs are lost across different glaucoma models. Commonalities of optic nerve crush and glaucoma-induced neurodegeneration are identified and discussed.
Collapse
Affiliation(s)
- Jiaxing Wang
- Emory Eye Center, Department of Ophthalmology, Emory University, 1365B Clifton Road NE, Atlanta, GA, 30322, USA
| | - Felix L. Struebing
- Center for Neuropathology and Prion Research, Ludwig Maximilian University of Munich, Germany,Department for Translational Brain Research, German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
| | - Eldon E. Geisert
- Emory Eye Center, Department of Ophthalmology, Emory University, 1365B Clifton Road NE, Atlanta, GA, 30322, USA,Corresponding author: (E.E. Geisert)
| |
Collapse
|
40
|
A Fair Assessment of Evaluation Tools for the Murine Microbead Occlusion Model of Glaucoma. Int J Mol Sci 2021; 22:ijms22115633. [PMID: 34073191 PMCID: PMC8199180 DOI: 10.3390/ijms22115633] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 05/14/2021] [Accepted: 05/19/2021] [Indexed: 02/06/2023] Open
Abstract
Despite being one of the most studied eye diseases, clinical translation of glaucoma research is hampered, at least in part, by the lack of validated preclinical models and readouts. The most popular experimental glaucoma model is the murine microbead occlusion model, yet the observed mild phenotype, mixed success rate, and weak reproducibility urge for an expansion of available readout tools. For this purpose, we evaluated various measures that reflect early onset glaucomatous changes in the murine microbead occlusion model. Anterior chamber depth measurements and scotopic threshold response recordings were identified as an outstanding set of tools to assess the model’s success rate and to chart glaucomatous damage (or neuroprotection in future studies), respectively. Both are easy-to-measure, in vivo tools with a fast acquisition time and high translatability to the clinic and can be used, whenever judged beneficial, in combination with the more conventional measures in present-day glaucoma research (i.e., intraocular pressure measurements and post-mortem histological analyses). Furthermore, we highlighted the use of dendritic arbor analysis as an alternative histological readout for retinal ganglion cell density counts.
Collapse
|
41
|
Hiscox LV, Schwarb H, McGarry MDJ, Johnson CL. Aging brain mechanics: Progress and promise of magnetic resonance elastography. Neuroimage 2021; 232:117889. [PMID: 33617995 PMCID: PMC8251510 DOI: 10.1016/j.neuroimage.2021.117889] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 02/12/2021] [Accepted: 02/15/2021] [Indexed: 02/07/2023] Open
Abstract
Neuroimaging techniques that can sensitivity characterize healthy brain aging and detect subtle neuropathologies have enormous potential to assist in the early detection of neurodegenerative conditions such as Alzheimer's disease. Magnetic resonance elastography (MRE) has recently emerged as a reliable, high-resolution, and especially sensitive technique that can noninvasively characterize tissue biomechanical properties (i.e., viscoelasticity) in vivo in the living human brain. Brain tissue viscoelasticity provides a unique biophysical signature of neuroanatomy that are representative of the composition and organization of the complex tissue microstructure. In this article, we detail how progress in brain MRE technology has provided unique insights into healthy brain aging, neurodegeneration, and structure-function relationships. We further discuss additional promising technical innovations that will enhance the specificity and sensitivity for brain MRE to reveal considerably more about brain aging as well as its potentially valuable role as an imaging biomarker of neurodegeneration. MRE sensitivity may be particularly useful for assessing the efficacy of rehabilitation strategies, assisting in differentiating between dementia subtypes, and in understanding the causal mechanisms of disease which may lead to eventual pharmacotherapeutic development.
Collapse
Affiliation(s)
- Lucy V Hiscox
- Department of Biomedical Engineering, University of Delaware, 150 Academy St. Newark, Newark, DE 19716, United States.
| | - Hillary Schwarb
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, United States; Interdisciplinary Health Sciences Institute, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | | | - Curtis L Johnson
- Department of Biomedical Engineering, University of Delaware, 150 Academy St. Newark, Newark, DE 19716, United States.
| |
Collapse
|
42
|
Kamel K, O'Brien CJ, Zhdanov AV, Papkovsky DB, Clark AF, Stamer WD, Irnaten M. Reduced Oxidative Phosphorylation and Increased Glycolysis in Human Glaucoma Lamina Cribrosa Cells. Invest Ophthalmol Vis Sci 2021; 61:4. [PMID: 33137197 PMCID: PMC7645202 DOI: 10.1167/iovs.61.13.4] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Purpose The lamina cribrosa (LC) is a key site of damage in glaucomatous optic neuropathy. We previously found that glaucoma LC cells have an increased profibrotic gene expression, with mitochondrial dysfunction in the form of decreased mitochondrial membrane potential. Altered cell bioenergetics have recently been reported in organ fibrosis and in cancer. In this study, we carried out a systematic mitochondrial bioenergetic assessment and measured markers of alternative sources of cellular energy in normal and glaucoma LC cells. Methods LC cells from three glaucoma donors and three age-matched normal controls were assessed using VICTOR X4 Perkin Elmer (Waltham, MA) plate reader with different phosphorescent and luminescent probes. adenosine triphosphate levels, oxygen consumption rate, and extracellular acidification were measured and normalized to total protein content. RNA and protein expression levels of MCT1, MCT4, MTFHD2, and GLS2 were quantified using real-time RT-PCR and Western blotting. Results Glaucoma LC cells contain significantly less adenosine triphosphate (P < .05) when supplied with either glucose or galactose. They also showed significantly diminished oxygen consumption in both basal and maximal respiration with more lactic acid contribution in ECA. Both mRNA and protein expression levels of MCT1, MCT4, MTHFD2, and GLS2 were significantly increased in glaucoma LC cells. Conclusions We demonstrate evidence of metabolic reprogramming (The Warburg effect) in glaucoma LC cells. Expression of markers of glycolysis, glutamine, and one carbon metabolism are elevated in glaucoma cells at both the mRNA and protein levels. A better understanding of bioenergetics in glaucoma may help in the development of new therapeutics.
Collapse
Affiliation(s)
- Khalid Kamel
- Department of Ophthalmology, Mater Misericordiae University Hospital, Dublin, Ireland
| | - Colm J O'Brien
- Department of Ophthalmology, Mater Misericordiae University Hospital, Dublin, Ireland.,School of Medicine and Medical Science, University College Dublin, Dublin, Ireland
| | - Alexander V Zhdanov
- School of Biochemistry & Cell Biology, University College Cork, Cork, Ireland
| | - Dmitri B Papkovsky
- School of Biochemistry & Cell Biology, University College Cork, Cork, Ireland
| | - Abbot F Clark
- Department of Pharmacology & Neuroscience and the North Texas Eye Research Institute, University of North Texas, Health Science Center, Fort Worth, Texas, United States
| | - W Daniel Stamer
- Department of Ophthalmology, Duke University, Durham, North Carolina, United States
| | - Mustapha Irnaten
- Department of Ophthalmology, Mater Misericordiae University Hospital, Dublin, Ireland
| |
Collapse
|
43
|
Al Hussein Al Awamlh S, Wareham LK, Risner ML, Calkins DJ. Insulin Signaling as a Therapeutic Target in Glaucomatous Neurodegeneration. Int J Mol Sci 2021; 22:4672. [PMID: 33925119 PMCID: PMC8124776 DOI: 10.3390/ijms22094672] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Revised: 04/24/2021] [Accepted: 04/27/2021] [Indexed: 01/28/2023] Open
Abstract
Glaucoma is a multifactorial disease that is conventionally managed with treatments to lower intraocular pressure (IOP). Despite these efforts, many patients continue to lose their vision. The degeneration of retinal ganglion cells (RGCs) and their axons in the optic tract that characterizes glaucoma is similar to neurodegeneration in other age-related disorders of the central nervous system (CNS). Identifying the different molecular signaling pathways that contribute to early neuronal dysfunction can be utilized for neuroprotective strategies that prevent degeneration. The discovery of insulin and its receptor in the CNS and retina led to exploration of the role of insulin signaling in the CNS. Historically, insulin was considered a peripherally secreted hormone that regulated glucose homeostasis, with no obvious roles in the CNS. However, a growing number of pre-clinical and clinical studies have demonstrated the potential of modulating insulin signaling in the treatment of neurodegenerative diseases. This review will highlight the role that insulin signaling plays in RGC neurodegeneration. We will focus on how this pathway can be therapeutically targeted to promote RGC axon survival and preserve vision.
Collapse
Affiliation(s)
- Sara Al Hussein Al Awamlh
- Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN 37232, USA; (S.A.H.A.A.); (L.K.W.); (M.L.R.)
| | - Lauren K. Wareham
- Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN 37232, USA; (S.A.H.A.A.); (L.K.W.); (M.L.R.)
| | - Michael L. Risner
- Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN 37232, USA; (S.A.H.A.A.); (L.K.W.); (M.L.R.)
| | - David J. Calkins
- Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN 37232, USA; (S.A.H.A.A.); (L.K.W.); (M.L.R.)
- Department of Ophthalmology & Visual Sciences, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| |
Collapse
|
44
|
Tribble JR, Otmani A, Sun S, Ellis SA, Cimaglia G, Vohra R, Jöe M, Lardner E, Venkataraman AP, Domínguez-Vicent A, Kokkali E, Rho S, Jóhannesson G, Burgess RW, Fuerst PG, Brautaset R, Kolko M, Morgan JE, Crowston JG, Votruba M, Williams PA. Nicotinamide provides neuroprotection in glaucoma by protecting against mitochondrial and metabolic dysfunction. Redox Biol 2021; 43:101988. [PMID: 33932867 PMCID: PMC8103000 DOI: 10.1016/j.redox.2021.101988] [Citation(s) in RCA: 74] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 04/06/2021] [Accepted: 04/20/2021] [Indexed: 12/16/2022] Open
Abstract
Nicotinamide adenine dinucleotide (NAD) is a REDOX cofactor and metabolite essential for neuronal survival. Glaucoma is a common neurodegenerative disease in which neuronal levels of NAD decline. We assess the effects of nicotinamide (a precursor to NAD) on retinal ganglion cells (the affected neuron in glaucoma) in normal physiological conditions and across a range of glaucoma relevant insults including mitochondrial stress and axon degenerative insults. We demonstrate retinal ganglion cell somal, axonal, and dendritic neuroprotection by nicotinamide in rodent models which represent isolated ocular hypertensive, axon degenerative, and mitochondrial degenerative insults. We performed metabolomics enriched for small molecular weight metabolites for the retina, optic nerve, and superior colliculus which demonstrates that ocular hypertension induces widespread metabolic disruption, including consistent changes to α-ketoglutaric acid, creatine/creatinine, homocysteine, and glycerophosphocholine. This metabolic disruption is prevented by nicotinamide. Nicotinamide provides further neuroprotective effects by increasing oxidative phosphorylation, buffering and preventing metabolic stress, and increasing mitochondrial size and motility whilst simultaneously dampening action potential firing frequency. These data support continued determination of the utility of long-term nicotinamide treatment as a neuroprotective therapy for human glaucoma. Nicotinamide is neuroprotective in cell and animal models that recapitulate isolated features of glaucoma. Systemic nicotinamide administration has limited molecular side-effects on visual system tissue under basal conditions. Nicotinamide provides a robust reversal in the disease metabolic profile of glaucomatous animals. Nicotinamide increases oxidative phosphorylation, buffers and prevents metabolic stress, and increases mitochondrial size.
Collapse
Affiliation(s)
- James R Tribble
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden.
| | - Amin Otmani
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden.
| | - Shanshan Sun
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK.
| | - Sevannah A Ellis
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Australia.
| | - Gloria Cimaglia
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden; School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK.
| | - Rupali Vohra
- Department of Veterinary and Animal Sciences, Pathobiological Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark; Department of Drug Design and Pharmacology, Eye Translational Research Unit, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.
| | - Melissa Jöe
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden.
| | - Emma Lardner
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden.
| | - Abinaya P Venkataraman
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden.
| | - Alberto Domínguez-Vicent
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden.
| | - Eirini Kokkali
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK.
| | - Seungsoo Rho
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK; Department of Ophthalmology, CHA Bundang Medical Center, CHA University, Seongnam, Republic of Korea.
| | - Gauti Jóhannesson
- Department of Clinical Sciences, Ophthalmology, Umeå University, Umeå, Sweden; Wallenberg Centre of Molecular Medicine, Umeå University, Umeå, Sweden.
| | | | - Peter G Fuerst
- WWAMI Medical Education Program, University of Idaho, Moscow, ID, USA.
| | - Rune Brautaset
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden.
| | - Miriam Kolko
- Department of Drug Design and Pharmacology, Eye Translational Research Unit, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark; Department of Ophthalmology, Copenhagen University Hospital, Rigshospitalet-Glostrup, Glostrup, Denmark.
| | - James E Morgan
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK; Cardiff Eye Unit, University Hospital Wales, Cardiff, UK; School of Medicine, Cardiff University, Cardiff, UK.
| | - Jonathan G Crowston
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Australia; Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore; Centre for Vision Research, Neuroscience and Behavioural Disorders, Duke-NUS, Singapore, Singapore.
| | - Marcela Votruba
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK; Cardiff Eye Unit, University Hospital Wales, Cardiff, UK.
| | - Pete A Williams
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden.
| |
Collapse
|
45
|
Oshitari T. Understanding intrinsic survival and regenerative pathways through in vivo and in vitro studies: implications for optic nerve regeneration. EXPERT REVIEW OF OPHTHALMOLOGY 2021. [DOI: 10.1080/17469899.2021.1912595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Toshiyuki Oshitari
- Department of Ophthalmology and Visual Science, Chiba University Graduate School of Medicine, Japan
- Department of Ophthalmology, International University of Health and Welfare School of Medicine, Narita, Japan
| |
Collapse
|
46
|
A cross-species analysis of systemic mediators of repair and complex tissue regeneration. NPJ Regen Med 2021; 6:21. [PMID: 33795702 PMCID: PMC8016993 DOI: 10.1038/s41536-021-00130-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 03/04/2021] [Indexed: 02/01/2023] Open
Abstract
Regeneration is an elegant and complex process informed by both local and long-range signals. Many current studies on regeneration are largely limited to investigations of local modulators within a canonical cohort of model organisms. Enhanced genetic tools increasingly enable precise temporal and spatial perturbations within these model regenerators, and these have primarily been applied to cells within the local injury site. Meanwhile, many aspects of broader spatial regulators of regeneration have not yet been examined with the same level of scrutiny. Recent studies have shed important insight into the significant effects of environmental cues and circulating factors on the regenerative process. These observations highlight that consideration of more systemic and possibly more broadly acting cues will also be critical to fully understand complex tissue regeneration. In this review, we explore the ways in which systemic cues and circulating factors affect the initiation of regeneration, the regenerative process, and its outcome. As this is a broad topic, we conceptually divide the factors based on their initial input as either external cues (for example, starvation and light/dark cycle) or internal cues (for example, hormones); however, all of these inputs ultimately lead to internal responses. We consider studies performed in a diverse set of organisms, including vertebrates and invertebrates. Through analysis of systemic mediators of regeneration, we argue that increased investigation of these "systemic factors" could reveal novel insights that may pave the way for a diverse set of therapeutic avenues.
Collapse
|
47
|
Bae HW, Choi W, Hwang AR, Lee SY, Seong GJ, Kim CY. Effects of Hypoxic Preconditioning and Vascular Endothelial Growth Factor on the Survival of Isolated Primary Retinal Ganglion Cells. Biomolecules 2021; 11:biom11030391. [PMID: 33800918 PMCID: PMC8002095 DOI: 10.3390/biom11030391] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Revised: 03/01/2021] [Accepted: 03/04/2021] [Indexed: 11/16/2022] Open
Abstract
This study aimed to investigate the effect of hypoxic preconditioning (HPC) on primary retinal ganglion cell (RGC) survival and the associated mechanism, including the role of vascular endothelial growth factor (VEGF). Retinas were separated from the enucleated eyeballs of Sprague-Dawley rats on postnatal days 1-4. RGCs were harvested using an immunopanning-magnetic separation system and maintained for 24 h in a defined medium. Hypoxic damage (0.3% O2) was inflicted on the cells using a CO₂ chamber. Anti-VEGF antibody (bevacizumab) was administered to RGCs exposed to hypoxic conditions, and RGC survival rate was compared to that of non-anti-VEGF antibody-treated RGCs. HPC lasting 4 h significantly increased RGC survival rate. In the RGCs exposed to hypoxic conditions for 4 h, VEGF mRNA and protein levels were significantly increased. Treatment with high dose bevacizumab (>1 mg/mL) countered HPC-mediated RGC survival. Protein kinase B and focal adhesion kinase levels were significantly increased in 4-h hypoxia-treated RGCs. HPC showed beneficial effects on primary RGC survival. However, only specifically controlled exposure to hypoxic conditions rendered neuroprotective effects. Strong inhibition of VEGF inhibited HPC-mediated RGC survival. These results indicate that VEGF may play an essential role in promoting cell survival under hypoxic conditions.
Collapse
Affiliation(s)
| | | | | | | | | | - Chan Yun Kim
- Correspondence: ; Tel.: +82-2-2228-3570; Fax: +82-2-312-0541
| |
Collapse
|
48
|
Calkins DJ. Adaptive responses to neurodegenerative stress in glaucoma. Prog Retin Eye Res 2021; 84:100953. [PMID: 33640464 DOI: 10.1016/j.preteyeres.2021.100953] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 02/08/2021] [Accepted: 02/19/2021] [Indexed: 12/12/2022]
Abstract
Glaucoma causes loss of vision through degeneration of the retinal ganglion cell (RGC) projection to the brain. The disease is characterized by sensitivity to intraocular pressure (IOP) conveyed at the optic nerve head, through which RGC axons pass unmyelinated to form the optic nerve. From this point, a pathogenic triumvirate comprising inflammatory, oxidative, and metabolic stress influence both proximal structures in the retina and distal structures in the optic projection. This review focuses on metabolic stress and how the optic projection may compensate through novel adaptive mechanisms to protect excitatory signaling to the brain. In the retina and proximal nerve head, the unmyelinated RGC axon segment is energy-inefficient, which leads to increased demand for adenosine-5'-triphosphate (ATP) at the risk of vulnerability to Ca2+-related metabolic and oxidative pressure. This vulnerability may underlie the bidirectional nature of progression. However, recent evidence highlights that the optic projection in glaucoma is not passive but rather demonstrates adaptive processes that may push back against neurodegeneration. In the retina, even as synaptic and dendritic pruning ensues, early progression involves enhanced excitability of RGCs. Enhancement involves depolarization of the resting membrane potential and increased response to light, independent of RGC morphological type. This response is axogenic, arising from increased levels and translocation of voltage-gated sodium channels (NaV) in the unmyelinated segment. During this same early period, large-scale networks of gap-junction coupled astrocytes redistribute metabolic resources to the optic projection stressed by elevated IOP to slow loss of axon function. This redistribution may reflect more local remodeling, as astrocyte processes respond to focal metabolic duress by boosting glycogen turnover in response to axonal activity in an effort to promote survival of the healthiest axons. Both enhanced excitability and metabolic redistribution are transient, indicating that the same adaptive mechanisms that apparently serve to slow progression ultimately may be too expensive for the system to sustain over longer periods.
Collapse
Affiliation(s)
- David J Calkins
- The Vanderbilt Eye Institute, Nashville, TN, USA; Vanderbilt Vision Research Center, Vanderbilt University Medical Center, 1161 21st Ave S, AA7100 Medical Center North Nashville, Tennessee, 37232, USA.
| |
Collapse
|
49
|
Jassim AH, Cavanaugh M, Shah JS, Willits R, Inman DM. Transcorneal Electrical Stimulation Reduces Neurodegenerative Process in a Mouse Model of Glaucoma. Ann Biomed Eng 2021; 49:858-870. [PMID: 32974756 PMCID: PMC7854493 DOI: 10.1007/s10439-020-02608-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 09/02/2020] [Indexed: 12/19/2022]
Abstract
Glaucoma is a neurodegenerative disease in which the retinal ganglion cell axons of the optic nerve degenerate concomitant with synaptic changes in the retina, leading finally to death of the retinal ganglion cells (RGCs). Electrical stimulation has been used to improve neural regeneration in a variety of systems, including in diseases of the retina. Therefore, the focus of this study was to investigate whether transcorneal electrical stimulation (TES) in the DBA2/J mouse model of glaucoma could improve retinal or optic nerve pathology and serve as a minimally invasive treatment option. Mice (10 months-old) received 21 sessions of TES over 8 weeks, after which we evaluated RGC number, axon number, and anterograde axonal transport using histology and immunohistochemistry. To gain insight into the mechanism of proposed protection, we also evaluated inflammation by quantifying CD3+ T-cells and Iba1+ microglia; perturbations in metabolism were shown via the ratio pAMPK to AMPK, and changes in trophic support were tested using protein capillary electrophoresis. We found that TES resulted in RGC axon protection, a reduction in inflammatory cells and their activation, improved energy homeostasis, and a reduction of the cell death-associated p75NTR. Collectively, the data indicated that TES maintained axons, decreased inflammation, and increased trophic factor support, in the form of receptor presence and energy homeostasis, suggesting that electrical stimulation impacts several facets of the neurodegenerative process in glaucoma.
Collapse
Affiliation(s)
- Assraa Hassan Jassim
- Department of Pharmaceutical Sciences, Northeast Ohio Medical University, Rootstown, OH, USA
- Department of Basic and Translational Sciences, University of Pennsylvania, Philadelphia, PA, USA
| | - McKay Cavanaugh
- Department of Biomedical Engineering, University of Akron, Akron, OH, USA
| | | | - Rebecca Willits
- Department of Biomedical Engineering, University of Akron, Akron, OH, USA.
- Department of Chemical Engineering, Northeastern University, Boston, MA, USA.
| | - Denise M Inman
- Department of Pharmaceutical Sciences, Northeast Ohio Medical University, Rootstown, OH, USA.
- North Texas Eye Research Institute, UNT-HSC, 3500 Camp Bowie Blvd, Fort Worth, TX, 76107, USA.
| |
Collapse
|
50
|
An alternative approach to produce versatile retinal organoids with accelerated ganglion cell development. Sci Rep 2021; 11:1101. [PMID: 33441707 PMCID: PMC7806597 DOI: 10.1038/s41598-020-79651-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 12/02/2020] [Indexed: 02/07/2023] Open
Abstract
Genetically complex ocular neuropathies, such as glaucoma, are a major cause of visual impairment worldwide. There is a growing need to generate suitable human representative in vitro and in vivo models, as there is no effective treatment available once damage has occured. Retinal organoids are increasingly being used for experimental gene therapy, stem cell replacement therapy and small molecule therapy. There are multiple protocols for the development of retinal organoids available, however, one potential drawback of the current methods is that the organoids can take between 6 weeks and 12 months on average to develop and mature, depending on the specific cell type wanted. Here, we describe and characterise a protocol focused on the generation of retinal ganglion cells within an accelerated four week timeframe without any external small molecules or growth factors. Subsequent long term cultures yield fully differentiated organoids displaying all major retinal cell types. RPE, Horizontal, Amacrine and Photoreceptors cells were generated using external factors to maintain lamination.
Collapse
|