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Zhang D, Hu F, Li T, Liu H, Li Q, Cheng Y, Zhang X, Xu P, Zhang S, Wu J. Platelet factor 4 attenuates inflammation of microglia and protects retinal ganglion cells in retinal excitotoxicity. Exp Eye Res 2025; 255:110352. [PMID: 40118133 DOI: 10.1016/j.exer.2025.110352] [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: 12/17/2024] [Revised: 03/18/2025] [Accepted: 03/19/2025] [Indexed: 03/23/2025]
Abstract
Glaucoma, a progressive optic neuropathy characterized by RGC degeneration and irreversible vision loss, currently affects approximately 76 million individuals globally. Despite conventional therapeutic strategies primarily targeting IOP reduction, the ongoing progression of vision loss in normotensive patients highlights an urgent need for alternative neuroprotective interventions. We employed a comprehensive experimental paradigm that integrated both in vivo and in vitro approaches. The in vivo component was utilized by NMDA-induced excitotoxicity involving Sprague-Dawley rats. In vitro analyses were conducted using R28 and BV2 cells. Quantitative assessments encompassed electroretinography, RGC survival, axonal integrity measurements, inflammatory marker profiles, flow cytometry, as well as molecular pathway analyses through immunofluorescence microscopy, Western blot analysis. Administration of PF4 (500 ng/ml) exhibited significant neuroprotective efficacy via multiple cellular mechanisms. Quantitative analyses indicated substantial preservation of RGC density (p < 0.001) alongside maintenance of inner plexiform layer thickness(p < 0.05) within the NMDA-induced model. PF4 treatment markedly attenuated microglial activation (p < 0.01) while modulating the inflammatory response-characterized by reduced expression of pro-inflammatory cytokines coupled with enhanced production of anti-inflammatory mediators. CTB tracing confirmed the preservation of both RGC axons and their projections. Molecular analyses revealed that PF4 may exerted its effects on RGC through different mechanisms: suppression of the Galectin-3/NLRP3-inflammasome/Caspase-1 pathway in microglia and enhancement of the CaMKII/CREB/BDNF neuroprotective cascade within RGCs; these protective effects can attenuate necroptosis independent from IOP modulation in retinal excitotoxicity. Our findings suggest that PF4 can protect RGCs through activate CaMKII/CREB/BDNF pathway induced by excitotoxicity. Moreover, it attenuates NLRP3 inflammasome activation via mediating Galectin-3 and thus decreasing necroptosis of RGCs. This study demonstrates that PF4 may possesses neuroprotective properties through simultaneous modulation across multiple cellular pathways in glaucomatous neurodegeneration, and emphasized the significance of immune-mediated mechanisms.
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Affiliation(s)
- Daowei Zhang
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China
| | - Fangyuan Hu
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China
| | - Ting Li
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China
| | - Hongli Liu
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China
| | - Qian Li
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China
| | - Yun Cheng
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China
| | - Xuejin Zhang
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China
| | - Ping Xu
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China
| | - Shenghai Zhang
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China; Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China; Key Laboratory of Myopia, Ministry of Health, Shanghai, China
| | - Jihong Wu
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China; Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China; Key Laboratory of Myopia, Ministry of Health, Shanghai, China.
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2
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Garton T, Smith MD, Kesharwani A, Gharagozloo M, Oh S, Na CH, Absinta M, Reich DS, Zack DJ, Calabresi PA. Myeloid lineage C3 induces reactive gliosis and neuronal stress during CNS inflammation. Nat Commun 2025; 16:3481. [PMID: 40216817 PMCID: PMC11992029 DOI: 10.1038/s41467-025-58708-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2024] [Accepted: 03/25/2025] [Indexed: 04/14/2025] Open
Abstract
Complement component C3 mediates pathology in CNS neurodegenerative diseases. Here we use scRNAseq of sorted C3-reporter positive cells from mouse brain and optic nerve to characterize C3 producing glia in experimental autoimmune encephalomyelitis (EAE), a model in which peripheral immune cells infiltrate the CNS, causing reactive gliosis and neuro-axonal pathology. We find that C3 expression in the early inflammatory stage of EAE defines disease-associated glial subtypes characterized by increased expression of genes associated with mTOR activation and cell metabolism. This pro-inflammatory subtype is abrogated with genetic C3 depletion, a finding confirmed with proteomic analyses. In addition, early optic nerve axonal injury and retinal ganglion cell oxidative stress, but not loss of post-synaptic density protein 95, are ameliorated by selective deletion of C3 in myeloid cells. These data suggest that in addition to C3b opsonization of post synaptic proteins leading to neuronal demise, C3 activation is a contributor to reactive glia in the optic nerve.
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Affiliation(s)
- Thomas Garton
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA
| | - Matthew D Smith
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA
| | - Ajay Kesharwani
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA
| | - Marjan Gharagozloo
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA
| | - Sungtaek Oh
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA
- Institute for Cell Engineering, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Chan-Hyun Na
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA
- Institute for Cell Engineering, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Martina Absinta
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA
- Translational Neuroradiology Section, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, USA
- Department of Biomedical Sciences, Humanitas University, Milan, Italy
- IRCCS Humanitas Reserach Hospital, Milan, Italy
| | - Daniel S Reich
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA
- Translational Neuroradiology Section, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Donald J Zack
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Peter A Calabresi
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA.
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA.
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD, 21205, USA.
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3
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Aviani MG, Menard F. Emerging Roles for MFG-E8 in Synapse Elimination. J Neurochem 2025; 169:e70009. [PMID: 39891478 DOI: 10.1111/jnc.70009] [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: 11/18/2024] [Revised: 01/15/2025] [Accepted: 01/17/2025] [Indexed: 02/03/2025]
Abstract
Synapse elimination is an essential process in the healthy nervous system and is dysregulated in many neuropathologies. Yet, the underlying molecular mechanisms and under what conditions they occur remain unclear. MFG-E8 is a secreted glycoprotein well known to act as an opsonin, tagging stressed and dying cells for engulfment by phagocytes. Opsonization of cells and debris by MFG-E8 for microglial phagocytosis in the CNS is well established, and its role in astrocytic phagocytosis, and trogocytosis-like engulfment of synapses is beginning to be explored. However, MFG-E8's function in other tissues is highly diverse, and evidence suggests that its role in the nervous system and on synapse elimination in particular may be more complex and varied than opsonization. In this review, we outline the documented direct and indirect effects of MFG-E8 on synapse elimination, while also proposing potential roles to be explored further, in particular, cytoskeletal reorganization of neurites and glia leading to synapse elimination by various mechanisms. Finally, we demonstrate the need for several open questions to be answered-chiefly, under what conditions might MFG-E8-mediated synapse elimination occur in favor of other mechanisms, and when might its activity be dysregulated, increasing unwanted synapse elimination and neurotoxicity?
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Affiliation(s)
- Marisa G Aviani
- Department of Biochemistry and Molecular Biology, I.K. Barber Faculty of Science, The University of British Columbia, Kelowna, British Columbia, Canada
| | - Fred Menard
- Department of Biochemistry and Molecular Biology, I.K. Barber Faculty of Science, The University of British Columbia, Kelowna, British Columbia, Canada
- Department of Chemistry, I.K. Barber Faculty of Science, The University of British Columbia, Kelowna, British Columbia, Canada
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Zhang C, Zhao S, Huang Z, Xue A, Liu H, Dai S, Zheng Z, Li Y, Guo X, Gu J, Zhang F, Wang F, Wang Y, Zhou X, Zhang S, Zhang H, Shen J, Chen J, Yin G. Macropinocytosis enhances foamy macrophage formation and cholesterol crystallization to activate NLRP3 inflammasome after spinal cord injury. Redox Biol 2025; 79:103469. [PMID: 39700693 PMCID: PMC11723182 DOI: 10.1016/j.redox.2024.103469] [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: 10/26/2024] [Revised: 11/30/2024] [Accepted: 12/12/2024] [Indexed: 12/21/2024] Open
Abstract
After spinal cord injury (SCI), phagocytes endocytose myelin debris to form foam cells, exacerbating the inflammatory response. It has been previously shown that macrophages become foam cells through the phagocytosis of myelin debris via receptor-dependent mechanisms after SCI. Blocking receptor-mediated endocytosis did not completely prevent foam cell formation, so we investigated receptor-independent endocytosis. Here, we revealed that foam cells formed after myelin debris internalization were predominantly macrophages rather than microglia. Receptor-independent macropinocytosis has an important position in foamy macrophage formation through engagement of myelin debris endocytosis after SCI. Mechanistic studies showed that cholesterol crystallization following macropinocytosis-mediated foamy macrophage formation promoted the reactive oxygen species (ROS) production and the NOD-like receptor protein 3 (NLRP3) inflammasome activation, increasing the secretion of interleukin-1β (IL-1β). Inhibition of macropinocytosis might reverse this effect, resulting in enhanced axonal regeneration and reduced neural apoptosis, thereby improving outcomes after SCI. Overall, our study revealed a previously unrecognized role for macropinocytosis in foamy macrophages formation after SCI, and confer a promising therapeutic strategy for SCI through focus on macropinocytosis.
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Affiliation(s)
- Chenxi Zhang
- Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing Medical University, Jiangsu, Nanjing, 210029, China; Department of Orthopedics, Suzhou Municipal Hospital, Nanjing Medical University, Jiangsu, Suzhou, 215000, China
| | - Shujie Zhao
- Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing Medical University, Jiangsu, Nanjing, 210029, China
| | - Zhenfei Huang
- Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing Medical University, Jiangsu, Nanjing, 210029, China
| | - Ao Xue
- Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing Medical University, Jiangsu, Nanjing, 210029, China
| | - Hao Liu
- Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing Medical University, Jiangsu, Nanjing, 210029, China
| | - Siming Dai
- Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing Medical University, Jiangsu, Nanjing, 210029, China
| | - Ziyang Zheng
- Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing Medical University, Jiangsu, Nanjing, 210029, China
| | - Yin Li
- Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing Medical University, Jiangsu, Nanjing, 210029, China
| | - Xiaodong Guo
- Department of Orthopedics, Wuhan Union Hospital of China, Huazhong University of Science and Technology, Hubei, Wuhan, 430022, China
| | - Jun Gu
- Department of Orthopedics, Xishan People's Hospital of Wuxi City, Southeast University, Jiangsu, Wuxi, 21405, China
| | - Feng Zhang
- Department of Orthopedics, Xuyi People's Hospital, Yangzhou University, Jiangsu, Xuyi, 211700, China
| | - Fubing Wang
- Department of Orthopedics, Xuyi People's Hospital, Yangzhou University, Jiangsu, Xuyi, 211700, China
| | - Yongxiang Wang
- Department of Orthopedics, Northern Jiangsu People's Hospital, Nanjing Medical University, Jiangsu, Yangzhou, 225001, China
| | - Xiaohua Zhou
- Department of Anesthesia and Perioperative Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing Medical University, Jiangsu, Nanjing, 210029, China
| | - Shujun Zhang
- Department of Orthopedics, Wuxi Ninth Hospital, Suzhou University, Jiangsu, Wuxi, 21405, China
| | - Hanwen Zhang
- Department of Pathophysiology, Nanjing Medical University, Jiangsu, Nanjing, 211166, China.
| | - Jun Shen
- Department of Orthopedics, Suzhou Municipal Hospital, Nanjing Medical University, Jiangsu, Suzhou, 215000, China.
| | - Jian Chen
- Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing Medical University, Jiangsu, Nanjing, 210029, China.
| | - Guoyong Yin
- Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing Medical University, Jiangsu, Nanjing, 210029, China.
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Yang SS, Brooks NAH, Da Silva DE, Gibon J, Islam H, Klegeris A. Extracellular ATP regulates phagocytic activity, mitochondrial respiration, and cytokine secretion of human astrocytic cells. Purinergic Signal 2025:10.1007/s11302-025-10066-x. [PMID: 39833586 DOI: 10.1007/s11302-025-10066-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2024] [Accepted: 01/03/2025] [Indexed: 01/22/2025] Open
Abstract
The two main glial cell types of the central nervous system (CNS), astrocytes and microglia, are responsible for neuroimmune homeostasis. Recent evidence indicates astrocytes can participate in removal of pathological structures by becoming phagocytic under conditions of neurodegenerative disease when microglia, the professional phagocytes, are impaired. We hypothesized that adenosine triphosphate (ATP), which acts as damage-associated molecular pattern (DAMP), when released at high concentrations into extracellular space, upregulates phagocytic activity of human astrocytes. This study is the first to measure changes in phagocytic activity and mitochondrial respiration of human astrocytic cells in response to extracellular ATP. We demonstrate that ATP-induced phagocytic activity of U118 MG astrocytic cells is accompanied by upregulated mitochondrial oxidative phosphorylation, which likely supports this energy-dependent process. Application of a selective antagonist A438079 provides evidence identifying astrocytic purinergic P2X7 receptor (P2X7R) as the potential regulator of their phagocytic function. We also report a rapid ATP-induced increase in intracellular calcium ([Ca2+]i), which could serve as regulator of both the phagocytic activity and mitochondrial metabolism, but this hypothesis will need to be tested in future studies. Since ATP upregulates interleukin (IL)-8 secretion by astrocytes but has no effect on their cytotoxicity towards neuronal cells, we conclude that extracellular ATP affects only specific functions of astrocytes. The selectivity of P2X7R-dependent regulation of astrocyte functions by extracellular ATP could allow targeting this receptor-ligand interaction to upregulate their phagocytic function. This could have beneficial outcomes in neurodegenerative disorders, such as Alzheimer's disease, that are characterized by reactive astrocytes and defective phagocytic processes.
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Affiliation(s)
- Sijie Shirley Yang
- Department of Biology, Faculty of Science, University of British Columbia Okanagan Campus, Kelowna, BC, V1V 1V7, Canada
| | - Noah A H Brooks
- Department of Biology, Faculty of Science, University of British Columbia Okanagan Campus, Kelowna, BC, V1V 1V7, Canada
| | - Dylan E Da Silva
- School of Health and Exercise Sciences, University of British Columbia Okanagan Campus, Kelowna, BC, V1V 1V7, Canada
| | - Julien Gibon
- Department of Biology, Faculty of Science, University of British Columbia Okanagan Campus, Kelowna, BC, V1V 1V7, Canada
| | - Hashim Islam
- School of Health and Exercise Sciences, University of British Columbia Okanagan Campus, Kelowna, BC, V1V 1V7, Canada.
| | - Andis Klegeris
- Department of Biology, Faculty of Science, University of British Columbia Okanagan Campus, Kelowna, BC, V1V 1V7, Canada.
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6
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Rombaut A, Brautaset R, Williams PA, Tribble JR. Intravitreal injection of the Galectin-3 inhibitor TD139 provides neuroprotection in a rat model of ocular hypertensive glaucoma. Mol Brain 2024; 17:84. [PMID: 39574161 PMCID: PMC11583433 DOI: 10.1186/s13041-024-01160-z] [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: 10/08/2024] [Accepted: 11/12/2024] [Indexed: 11/24/2024] Open
Abstract
Neuroinflammation is a significant contributor to the pathology of glaucoma. Targeting key-mediators in this process is a realistic option to slow disease progression. Galectin-3 is a β-galactoside binding lectin that has been associated with inflammation in both systemic and central nervous system diseases. Elevated Galectin-3 has recently been detected in multiple animal models of glaucoma and inhibiting Galectin-3 using an intravitreal injection of TD139 (a Galectin-3 small molecule inhibitor) is neuroprotective. We queried whether this neuroprotective effect was translatable to another animal model and species. TD139 was intravitreally injected, in a rat ocular hypertensive model of glaucoma, 3 days after the induction of ocular hypertension (at peak intraocular pressure). Retinal ganglion cell survival and glial morphological markers were quantified. The degeneration of retinal ganglion cells was prevented by TD139 injection, but gross glial markers remained unaffected. These data confirm that the intravitreal injection of TD139 is neuroprotective in a rat ocular hypertensive model of glaucoma, while suggesting that the inhibition of Galectin-3 is not sufficient to alter the gross inflammatory outcome.
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Affiliation(s)
- Anne Rombaut
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden
| | - Rune Brautaset
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden
| | - Pete A Williams
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden
| | - James R Tribble
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden.
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7
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Girkin CA, Strickland RG, Somerville MM, Garner MA, Grossman GH, Blake A, Kumar N, Ianov L, Fazio MA, Clark ME, Gross AK. Acute ocular hypertension in the living human eye: Model description and initial cellular responses to elevated intraocular pressure. Vision Res 2024; 223:108465. [PMID: 39173459 PMCID: PMC11444249 DOI: 10.1016/j.visres.2024.108465] [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: 06/05/2024] [Revised: 08/02/2024] [Accepted: 08/02/2024] [Indexed: 08/24/2024]
Abstract
This initial methods study presents the initial immunohistochemical and transcriptomic changes in the optic nerve head and retina from three research-consented brain-dead organ donors following prolonged and transient intraocular pressure (IOP) elevation. In this initial study, research-consented brain-dead organ donors were exposed to unilateral elevation of IOP for 7.5 h (Donor 1), 30 h (Donor 2), and 1 h (Donor 3) prior to organ procurement. Optic nerve tissue and retinal tissue was obtained following organ procurement for immunohistological and transcriptomic analysis. Optic nerve sections in Donor 1 exposed to 7.5-hours of unilateral sub-ischemic IOP elevation demonstrated higher levels of protein expression of the astrocytic marker, glial fibrillary acidic protein (GFAP), within the lamina cribrosa with greatest expression inferior temporally in the treated eye compared to control. Spatial transcriptomic analysis performed on optic nerve head tissues from Donor 2 exposed to 30 h of unilateral IOP elevation demonstrated differential transcription of mRNA across laminar and scleral regions. Immunohistochemistry of retinal sections from Donor 2 exhibited higher GFAP and IBA1 expression in the treated eye compared with control, but this was not observed in Donor 3, which was exposed to only 1-hour of IOP elevation. While there were no differences in GFAP protein expression in the retina following the 1-hour IOP elevation in Donor 3, there were higher levels of transcription of GFAP in the inner nuclear layer, and CD44 in the retinal ganglion cell layer, indicative of astrocytic and Müller glial reactivity as well as an early inflammatory response, respectively. We found that transcriptomic differences can be observed across treated and control eyes following unilateral elevation of IOP in brain dead organ donors. The continued development of this model affords the unique opportunity to define the acute mechanotranscriptomic response of the optic nerve head, evaluate the injury and repair mechanisms in the retina in response to IOP elevation, and enable correlation of in vivo imaging and functional testing with ex vivo cellular responses for the first time in the living human eye.
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Affiliation(s)
- Christopher A Girkin
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA; Department of Neurobiology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Ryan G Strickland
- Department of Neurobiology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - McKenna M Somerville
- Department of Neurobiology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Mary Anne Garner
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA; Department of Neurobiology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | | | - Alan Blake
- Advancing Sight Network, Birmingham, AL, USA
| | - Nilesh Kumar
- IRCP-Biological Data Sciences, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Lara Ianov
- Department of Neurobiology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA; IRCP-Biological Data Sciences, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Massimo A Fazio
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Mark E Clark
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Alecia K Gross
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA; Department of Neurobiology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA.
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8
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Cullen PF, Gammerdinger WJ, Sui SJH, Mazumder AG, Sun D. Transcriptional profiling of retinal astrocytes identifies a specific marker and points to functional specialization. Glia 2024; 72:1604-1628. [PMID: 38785355 PMCID: PMC11262981 DOI: 10.1002/glia.24571] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Revised: 04/19/2024] [Accepted: 05/13/2024] [Indexed: 05/25/2024]
Abstract
Astrocyte heterogeneity is an increasingly prominent research topic, and studies in the brain have demonstrated substantial variation in astrocyte form and function, both between and within regions. In contrast, retinal astrocytes are not well understood and remain incompletely characterized. Along with optic nerve astrocytes, they are responsible for supporting retinal ganglion cell axons and an improved understanding of their role is required. We have used a combination of microdissection and Ribotag immunoprecipitation to isolate ribosome-associated mRNA from retinal astrocytes and investigate their transcriptome, which we also compared to astrocyte populations in the optic nerve. Astrocytes from these regions are transcriptionally distinct, and we identified retina-specific astrocyte genes and pathways. Moreover, although they share much of the "classical" gene expression patterns of astrocytes, we uncovered unexpected variation, including in genes related to core astrocyte functions. We additionally identified the transcription factor Pax8 as a highly specific marker of retinal astrocytes and demonstrated that these astrocytes populate not only the retinal surface, but also the prelaminar region at the optic nerve head. These findings are likely to contribute to a revised understanding of the role of astrocytes in the retina.
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Affiliation(s)
- Paul F Cullen
- Department of Ophthalmology, Schepens Eye Research Institute of Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114 USA
| | - William J Gammerdinger
- Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA
| | - Shannan J Ho Sui
- Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA
| | - Arpan G Mazumder
- Department of Ophthalmology, Schepens Eye Research Institute of Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114 USA
| | - Daniel Sun
- Department of Ophthalmology, Schepens Eye Research Institute of Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114 USA
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Kapic A, Zaman K, Nguyen V, Neagu GC, Sumien N, Prokai L, Prokai-Tatrai K. The Prodrug DHED Delivers 17β-Estradiol into the Retina for Protection of Retinal Ganglion Cells and Preservation of Visual Function in an Animal Model of Glaucoma. Cells 2024; 13:1126. [PMID: 38994978 PMCID: PMC11240555 DOI: 10.3390/cells13131126] [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: 06/04/2024] [Revised: 06/25/2024] [Accepted: 06/26/2024] [Indexed: 07/13/2024] Open
Abstract
We report a three-pronged phenotypic evaluation of the bioprecursor prodrug 10β,17β-dihydroxyestra-1,4-dien-3-one (DHED) that selectively produces 17β-estradiol (E2) in the retina after topical administration and halts glaucomatous neurodegeneration in a male rat model of the disease. Ocular hypertension (OHT) was induced by hyperosmotic saline injection into an episcleral vein of the eye. Animals received daily DHED eye drops for 12 weeks. Deterioration of visual acuity and contrast sensitivity by OHT in these animals were markedly prevented by the DHED-derived E2 with concomitant preservation of retinal ganglion cells and their axons. In addition, we utilized targeted retina proteomics and a previously established panel of proteins as preclinical biomarkers in the context of OHT-induced neurodegeneration as a characteristic process of the disease. The prodrug treatment provided retina-targeted remediation against the glaucomatous dysregulations of these surrogate endpoints without increasing circulating E2 levels. Collectively, the demonstrated significant neuroprotective effect by the DHED-derived E2 in the selected animal model of glaucoma supports the translational potential of our presented ocular neuroprotective approach owing to its inherent therapeutic safety and efficacy.
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Affiliation(s)
| | | | | | | | | | | | - Katalin Prokai-Tatrai
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX 76107, USA; (A.K.); (K.Z.); (V.N.); (G.C.N.); (N.S.); (L.P.)
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10
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Chaudhary P, Lockwood H, Stowell C, Bushong E, Reynaud J, Yang H, Gardiner SK, Wiliams G, Williams I, Ellisman M, Marsh-Armstrong N, Burgoyne C. Retrolaminar Demyelination of Structurally Intact Axons in Nonhuman Primate Experimental Glaucoma. Invest Ophthalmol Vis Sci 2024; 65:36. [PMID: 38407858 PMCID: PMC10902877 DOI: 10.1167/iovs.65.2.36] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Accepted: 01/28/2024] [Indexed: 02/27/2024] Open
Abstract
Purpose To determine if structurally intact, retrolaminar optic nerve (RON) axons are demyelinated in nonhuman primate (NHP) experimental glaucoma (EG). Methods Unilateral EG NHPs (n = 3) were perfusion fixed, EG and control eyes were enucleated, and foveal Bruch's membrane opening (FoBMO) 30° sectoral axon counts were estimated. Optic nerve heads were trephined; serial vibratome sections (VSs) were imaged and colocalized to a fundus photograph establishing their FoBMO location. The peripheral neural canal region within n = 5 EG versus control eye VS comparisons was targeted for scanning block-face electron microscopic reconstruction (SBEMR) using micro-computed tomographic reconstructions (µCTRs) of each VS. Posterior laminar beams within each µCTR were segmented, allowing a best-fit posterior laminar surface (PLS) to be colocalized into its respective SBEMR. Within each SBEMR, up to 300 axons were randomly traced until they ended (nonintact) or left the block (intact). For each intact axon, myelin onset was identified and myelin onset distance (MOD) was measured relative to the PLS. For each EG versus control SBEMR comparison, survival analyses compared EG and control MOD. Results MOD calculations were successful in three EG and five control eye SBEMRs. Within each SBEMR comparison, EG versus control eye axon loss was -32.9%, -8.3%, and -15.2% (respectively), and MOD was increased in the EG versus control SBEMR (P < 0.0001 for each EG versus control SBEMR comparison). When data from all three EG eye SBEMRs were compared to all five control eye SBEMRs, MOD was increased within the EG eyes. Conclusions Structurally intact, RON axons are demyelinated in NHP early to moderate EG. Studies to determine their functional status are indicated.
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Affiliation(s)
- Priya Chaudhary
- Optic Nerve Head Research Laboratory, Legacy Devers Eye Institute, Legacy Research Institute, Portland, Oregon, United States
- Discoveries in Sight, Devers Eye Institute, Legacy Research Institute, Portland, Oregon, United States
| | - Howard Lockwood
- Optic Nerve Head Research Laboratory, Legacy Devers Eye Institute, Legacy Research Institute, Portland, Oregon, United States
- Discoveries in Sight, Devers Eye Institute, Legacy Research Institute, Portland, Oregon, United States
| | - Cheri Stowell
- Optic Nerve Head Research Laboratory, Legacy Devers Eye Institute, Legacy Research Institute, Portland, Oregon, United States
- Discoveries in Sight, Devers Eye Institute, Legacy Research Institute, Portland, Oregon, United States
| | - Eric Bushong
- National Center for Microscopy & Imaging Research, UCSD, La Jolla, California, United States
| | - Juan Reynaud
- Optic Nerve Head Research Laboratory, Legacy Devers Eye Institute, Legacy Research Institute, Portland, Oregon, United States
- Discoveries in Sight, Devers Eye Institute, Legacy Research Institute, Portland, Oregon, United States
| | - Hongli Yang
- Optic Nerve Head Research Laboratory, Legacy Devers Eye Institute, Legacy Research Institute, Portland, Oregon, United States
- Discoveries in Sight, Devers Eye Institute, Legacy Research Institute, Portland, Oregon, United States
| | - Stuart K Gardiner
- Discoveries in Sight, Devers Eye Institute, Legacy Research Institute, Portland, Oregon, United States
| | - Galen Wiliams
- Optic Nerve Head Research Laboratory, Legacy Devers Eye Institute, Legacy Research Institute, Portland, Oregon, United States
- Discoveries in Sight, Devers Eye Institute, Legacy Research Institute, Portland, Oregon, United States
| | - Imee Williams
- Optic Nerve Head Research Laboratory, Legacy Devers Eye Institute, Legacy Research Institute, Portland, Oregon, United States
- Discoveries in Sight, Devers Eye Institute, Legacy Research Institute, Portland, Oregon, United States
| | - Mark Ellisman
- National Center for Microscopy & Imaging Research, UCSD, La Jolla, California, United States
| | - Nick Marsh-Armstrong
- Department of Ophthalmology, University of California, Davis, California, United States
| | - Claude Burgoyne
- Optic Nerve Head Research Laboratory, Legacy Devers Eye Institute, Legacy Research Institute, Portland, Oregon, United States
- Discoveries in Sight, Devers Eye Institute, Legacy Research Institute, Portland, Oregon, United States
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11
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Aubrey LD, Ninkina N, Ulamec SM, Abramycheva NY, Vasili E, Devine OM, Wilkinson M, Mackinnon E, Limorenko G, Walko M, Muwanga S, Amadio L, Peters OM, Illarioshkin SN, Outeiro TF, Ranson NA, Brockwell DJ, Buchman VL, Radford SE. Substitution of Met-38 to Ile in γ-synuclein found in two patients with amyotrophic lateral sclerosis induces aggregation into amyloid. Proc Natl Acad Sci U S A 2024; 121:e2309700120. [PMID: 38170745 PMCID: PMC10786281 DOI: 10.1073/pnas.2309700120] [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: 06/08/2023] [Accepted: 11/17/2023] [Indexed: 01/05/2024] Open
Abstract
α-, β-, and γ-Synuclein are intrinsically disordered proteins implicated in physiological processes in the nervous system of vertebrates. α-synuclein (αSyn) is the amyloidogenic protein associated with Parkinson's disease and certain other neurodegenerative disorders. Intensive research has focused on the mechanisms that cause αSyn to form amyloid structures, identifying its NAC region as being necessary and sufficient for amyloid assembly. Recent work has shown that a 7-residue sequence (P1) is necessary for αSyn amyloid formation. Although γ-synuclein (γSyn) is 55% identical in sequence to αSyn and its pathological deposits are also observed in association with neurodegenerative conditions, γSyn is resilient to amyloid formation in vitro. Here, we report a rare single nucleotide polymorphism (SNP) in the SNCG gene encoding γSyn, found in two patients with amyotrophic lateral sclerosis (ALS). The SNP results in the substitution of Met38 with Ile in the P1 region of the protein. These individuals also had a second, common and nonpathological, SNP in SNCG resulting in the substitution of Glu110 with Val. In vitro studies demonstrate that the Ile38 variant accelerates amyloid fibril assembly. Contrastingly, Val110 retards fibril assembly and mitigates the effect of Ile38. Substitution of residue 38 with Leu had little effect, while Val retards, and Ala increases the rate of amyloid formation. Ile38 γSyn also results in the formation of γSyn-containing inclusions in cells. The results show how a single point substitution can enhance amyloid formation of γSyn and highlight the P1 region in driving amyloid formation in another synuclein family member.
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Affiliation(s)
- Liam D. Aubrey
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Science, University of Leeds, LeedsLS2 9JT, United Kingdom
| | - Natalia Ninkina
- School of Biosciences, Cardiff University, CardiffCF10 3AX, United Kingdom
- Department of Pharmacology and Clinical Pharmacology, Belgorod State National Research University, Belgorod308015, Russian Federation
| | - Sabine M. Ulamec
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Science, University of Leeds, LeedsLS2 9JT, United Kingdom
| | - Natalia Y. Abramycheva
- Laboratory of Neurobiology and Tissue Engineering, Brain Science Institute, Research Center of Neurology, Moscow125367, Russia
| | - Eftychia Vasili
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, LausanneCH-1015, Switzerland
| | - Oliver M. Devine
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Science, University of Leeds, LeedsLS2 9JT, United Kingdom
| | - Martin Wilkinson
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Science, University of Leeds, LeedsLS2 9JT, United Kingdom
| | - Eilish Mackinnon
- School of Biosciences, Cardiff University, CardiffCF10 3AX, United Kingdom
| | - Galina Limorenko
- School of Biosciences, Cardiff University, CardiffCF10 3AX, United Kingdom
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, LausanneCH-1015, Switzerland
| | - Martin Walko
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Science, University of Leeds, LeedsLS2 9JT, United Kingdom
- Astbury Centre for Structural Molecular Biology, School of Chemistry, University of Leeds, LeedsLS2 9JT, United Kingdom
| | - Sarah Muwanga
- School of Biosciences, Cardiff University, CardiffCF10 3AX, United Kingdom
| | - Leonardo Amadio
- School of Biosciences, Cardiff University, CardiffCF10 3AX, United Kingdom
| | - Owen M. Peters
- School of Biosciences, Cardiff University, CardiffCF10 3AX, United Kingdom
| | - Sergey N. Illarioshkin
- Laboratory of Neurobiology and Tissue Engineering, Brain Science Institute, Research Center of Neurology, Moscow125367, Russia
| | - Tiago F. Outeiro
- Department of Experimental Neurodegeneration, Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, Göttingen37075, Germany
- Max Planck Institute for Multidisciplinary Sciences, Goettingen37075, Germany
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle Upon TyneNE2 4HH, United Kingdom
- Scientific employee with a honorary contract at Deutsches Zentrum für Neurodegenerative Erkrankungen, Göttingen37075, Germany
| | - Neil A. Ranson
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Science, University of Leeds, LeedsLS2 9JT, United Kingdom
| | - David J. Brockwell
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Science, University of Leeds, LeedsLS2 9JT, United Kingdom
| | - Vladimir L. Buchman
- School of Biosciences, Cardiff University, CardiffCF10 3AX, United Kingdom
- Department of Pharmacology and Clinical Pharmacology, Belgorod State National Research University, Belgorod308015, Russian Federation
| | - Sheena E. Radford
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Science, University of Leeds, LeedsLS2 9JT, United Kingdom
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12
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Benson CA, Olson KL, Patwa S, Kauer SD, King JF, Waxman SG, Tan AM. Conditional Astrocyte Rac1KO Attenuates Hyperreflexia after Spinal Cord Injury. J Neurosci 2024; 44:e1670222023. [PMID: 37963762 PMCID: PMC10851682 DOI: 10.1523/jneurosci.1670-22.2023] [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: 09/01/2022] [Revised: 08/24/2023] [Accepted: 09/19/2023] [Indexed: 11/16/2023] Open
Abstract
Spasticity is a hyperexcitability disorder that adversely impacts functional recovery and rehabilitative efforts after spinal cord injury (SCI). The loss of evoked rate-dependent depression (RDD) of the monosynaptic H-reflex is indicative of hyperreflexia, a physiological sign of spasticity. Given the intimate relationship between astrocytes and neurons, that is, the tripartite synapse, we hypothesized that astrocytes might have a significant role in post-injury hyperreflexia and plasticity of neighboring neuronal synaptic dendritic spines. Here, we investigated the effect of selective Rac1KO in astrocytes (i.e., adult male and female mice, transgenic cre-flox system) on SCI-induced spasticity. Three weeks after a mild contusion SCI, control Rac1wt animals displayed a loss of H-reflex RDD, that is, hyperreflexia. In contrast, transgenic animals with astrocytic Rac1KO demonstrated near-normal H-reflex RDD similar to pre-injury levels. Reduced hyperreflexia in astrocytic Rac1KO animals was accompanied by a loss of thin-shaped dendritic spine density on α-motor neurons in the ventral horn. In SCI-Rac1wt animals, as expected, we observed the development of dendritic spine dysgenesis on α-motor neurons associated with spasticity. As compared with WT animals, SCI animals with astrocytic Rac1KO expressed increased levels of the glial-specific glutamate transporter, glutamate transporter-1 in the ventral spinal cord, potentially enhancing glutamate clearance from the synaptic cleft and reducing hyperreflexia in astrocytic Rac1KO animals. Taken together, our findings show for the first time that Rac1 activity in astrocytes can contribute to hyperreflexia underlying spasticity following SCI. These results reveal an opportunity to target cell-specific molecular regulators of H-reflex excitability to manage spasticity after SCI.Significance Statement Spinal cord injury leads to stretch reflex hyperexcitability, which underlies the clinical symptom of spasticity. This study shows for the first time that astrocytic Rac1 contributes to the development of hyperreflexia after SCI. Specifically, astrocytic Rac1KO reduced SCI-related H-reflex hyperexcitability, decreased dendritic spine dysgenesis on α-motor neurons, and elevated the expression of the astrocytic glutamate transporter-1 (GLT-1). Overall, this study supports a distinct role for astrocytic Rac1 signaling within the spinal reflex circuit and the development of SCI-related spasticity.
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Affiliation(s)
- Curtis A Benson
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut 06510
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut 06516
| | - Kai-Lan Olson
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut 06510
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut 06516
| | - Siraj Patwa
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut 06510
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut 06516
| | - Sierra D Kauer
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut 06510
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut 06516
| | - Jared F King
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut 06510
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut 06516
| | - Stephen G Waxman
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut 06510
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut 06516
| | - Andrew M Tan
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut 06510,
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut 06516
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13
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Yuan WQ, Huang WP, Jiang YC, Xu H, Duan CS, Chen NH, Liu YJ, Fu XM. The function of astrocytes and their role in neurological diseases. Eur J Neurosci 2023; 58:3932-3961. [PMID: 37831013 DOI: 10.1111/ejn.16160] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 09/11/2023] [Accepted: 09/13/2023] [Indexed: 10/14/2023]
Abstract
Astrocytes have countless links with neurons. Previously, astrocytes were only considered a scaffold of neurons; in fact, astrocytes perform a variety of functions, including providing support for neuronal structures and energy metabolism, offering isolation and protection and influencing the formation, function and elimination of synapses. Because of these functions, astrocytes play an critical role in central nervous system (CNS) diseases. The regulation of the secretiory factors, receptors, channels and pathways of astrocytes can effectively inhibit the occurrence and development of CNS diseases, such as neuromyelitis optica (NMO), multiple sclerosis, Alzheimer's disease (AD), Parkinson's disease (PD) and Huntington's disease. The expression of aquaporin 4 in AS is directly related to NMO and indirectly involved in the clearance of Aβ and tau proteins in AD. Connexin 43 has a bidirectional effect on glutamate diffusion at different stages of stroke. Interestingly, astrocytes reduce the occurrence of PD through multiple effects such as secretion of related factors, mitochondrial autophagy and aquaporin 4. Therefore, this review is focused on the structure and function of astrocytes and the correlation between astrocytes and CNS diseases and drug treatment to explore the new functions of astrocytes with the astrocytes as the target. This, in turn, would provide a reference for the development of new drugs to protect neurons and promote the recovery of nerve function.
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Affiliation(s)
- Wen-Qin Yuan
- College of Pharmacy, Jiangxi University of Chinese Medicine, Nanchang, China
| | - Wei-Peng Huang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica and Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- College of Pharmacy, Minzu University of China, Beijing, China
| | - Yang-Chao Jiang
- College of Pharmacy, Jiangxi University of Chinese Medicine, Nanchang, China
| | - Hao Xu
- College of Economics and Management, Jiangxi University of Chinese Medicine, Nanchang, China
| | - Chong-Shen Duan
- College of Pharmacy, Jiangxi University of Chinese Medicine, Nanchang, China
| | - Nai-Hong Chen
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica and Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Ying-Jiao Liu
- College of Pharmacy, Jiangxi University of Chinese Medicine, Nanchang, China
| | - Xiao-Mei Fu
- College of Pharmacy, Jiangxi University of Chinese Medicine, Nanchang, China
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14
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Zhu Y, Wang R, Pappas AC, Seifert P, Savol A, Sadreyev RI, Sun D, Jakobs TC. Astrocytes in the Optic Nerve Are Heterogeneous in Their Reactivity to Glaucomatous Injury. Cells 2023; 12:2131. [PMID: 37681863 PMCID: PMC10486930 DOI: 10.3390/cells12172131] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 07/14/2023] [Accepted: 08/18/2023] [Indexed: 09/09/2023] Open
Abstract
The optic nerve head is thought to be the site of initial injury to retinal ganglion cell injury in glaucoma. In the initial segment of the optic nerve directly behind the globe, the ganglion cell axons are unmyelinated and come into direct contact to astrocytes, suggesting that astrocytes may play a role in the pathology of glaucoma. As in other parts of the CNS, optic nerve head astrocytes respond to injury by characteristic changes in cell morphology and gene expression profile. Using RNA-sequencing of glaucomatous optic nerve heads, single-cell PCR, and an in-vivo assay, we demonstrate that an up-regulation of astrocytic phagocytosis is an early event after the onset of increased intraocular pressure. We also show that astrocytes in the glial lamina of the optic nerve are apparently functionally heterogeneous. At any time, even in naïve nerves, some of the cells show signs of reactivity-process hypertrophy, high phagocytic activity, and expression of genetic markers of reactivity whereas neighboring cells apparently are inactive. A period of increased intraocular pressure moves more astrocytes towards the reactive phenotype; however, some cells remain unreactive even in glaucomatous nerves.
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Affiliation(s)
- Ying Zhu
- Department of Ophthalmology, Massachusetts Eye and Ear Infirmary/Schepens Eye Research Institute, Harvard Medical School, 20 Staniford Street, Boston, MA 02114, USA
- Department of Ophthalmology, Stanford University, 1651 Page Mill Road, Palo Alto, CA 94304, USA
| | - Rui Wang
- Department of Ophthalmology, Massachusetts Eye and Ear Infirmary/Schepens Eye Research Institute, Harvard Medical School, 20 Staniford Street, Boston, MA 02114, USA
- Department of Ophthalmology, The First Affiliated Hospital of Northwest University, Xi’an 710002, China
| | - Anthony C. Pappas
- Department of Ophthalmology, Massachusetts Eye and Ear Infirmary/Schepens Eye Research Institute, Harvard Medical School, 20 Staniford Street, Boston, MA 02114, USA
| | - Philip Seifert
- Department of Ophthalmology, Massachusetts Eye and Ear Infirmary/Schepens Eye Research Institute, Harvard Medical School, 20 Staniford Street, Boston, MA 02114, USA
| | - Andrej Savol
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA
- Department of Pathology, Massachusetts General Hospital and Harvard Medical School, 185 Cambridge St., Boston, MA 02114, USA
| | - Ruslan I. Sadreyev
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA
- Department of Pathology, Massachusetts General Hospital and Harvard Medical School, 185 Cambridge St., Boston, MA 02114, USA
| | - Daniel Sun
- Department of Ophthalmology, Massachusetts Eye and Ear Infirmary/Schepens Eye Research Institute, Harvard Medical School, 20 Staniford Street, Boston, MA 02114, USA
| | - Tatjana C. Jakobs
- Department of Ophthalmology, Massachusetts Eye and Ear Infirmary/Schepens Eye Research Institute, Harvard Medical School, 20 Staniford Street, Boston, MA 02114, USA
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15
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Cheng J, Wang W, Xia Y, Li Y, Jia J, Xiao G. Regulators of phagocytosis as pharmacologic targets for stroke treatment. Front Pharmacol 2023; 14:1122527. [PMID: 37601043 PMCID: PMC10433754 DOI: 10.3389/fphar.2023.1122527] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 07/20/2023] [Indexed: 08/22/2023] Open
Abstract
Stroke, including ischemic and hemorrhagic stroke, causes massive cell death in the brain, which is followed by secondary inflammatory injury initiated by disease-associated molecular patterns released from dead cells. Phagocytosis, a cellular process of engulfment and digestion of dead cells, promotes the resolution of inflammation and repair following stroke. However, professional or non-professional phagocytes also phagocytose stressed but viable cells in the brain or excessively phagocytose myelin sheaths or prune synapses, consequently exacerbating brain injury and impairing repair following stroke. Phagocytosis includes the smell, eating and digestion phases. Notably, efficient phagocytosis critically depends on phagocyte capacity to take up dead cells continually due to the limited number of phagocytes vs. dead cells after injury. Moreover, phenotypic polarization of phagocytes occurring after phagocytosis is also essential to the proresolving and prorepair properties of phagocytosis. Much has been learned about the molecular signals and regulatory mechanisms governing the sense and recognition of dead cells by phagocytes during the smell and eating phase following stroke. However, some key areas remain extremely understudied, including the mechanisms involved in digestion regulation, continual phagocytosis and phagocytosis-induced phenotypic switching following stroke. Here, we summarize new discoveries related to the molecular mechanisms and multifaceted effects of phagocytosis on brain injury and repair following stroke and highlight the knowledge gaps in poststroke phagocytosis. We suggest that advancing the understanding of poststroke phagocytosis will help identify more biological targets for stroke treatment.
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Affiliation(s)
- Jian Cheng
- Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, China
- Jiangsu Key Laboratory of Neuropsychiatric Diseases, Institute of Neuroscience, Soochow University, Suzhou, China
| | - Wei Wang
- Department of Pharmacy, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Yiqing Xia
- Jiangsu Key Laboratory of Neuropsychiatric Diseases, Institute of Neuroscience, Soochow University, Suzhou, China
| | - Yi Li
- Academy of Pharmacy, Xi’an Jiaotong-Liverpool University, Suzhou, China
| | - Jia Jia
- Jiangsu Key Laboratory of Neuropsychiatric Diseases, College of Pharmaceutical Sciences, Soochow University, Suzhou, China
| | - Guodong Xiao
- Suzhou Clinical Research Center of Neurological Disease, Department of Neurology, The Second Affiliated Hospital of Soochow University, Suzhou, China
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16
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Yang SS, Simtchouk S, Gibon J, Klegeris A. Regulation of the phagocytic activity of astrocytes by neuroimmune mediators endogenous to the central nervous system. PLoS One 2023; 18:e0289169. [PMID: 37498903 PMCID: PMC10374099 DOI: 10.1371/journal.pone.0289169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Accepted: 07/11/2023] [Indexed: 07/29/2023] Open
Abstract
The phagocytic activity of glial cells is essential for maintaining normal brain activity, and its dysfunction may contribute to the central nervous system (CNS) pathologies, including neurodegenerative diseases. Phagocytic activity is one of the well-established neuroimmune functions of microglia. Although emerging evidence indicates that astrocytes can also function as CNS phagocytes in humans and rodents, limited information is available about the molecular mechanism regulating this function. To address this knowledge gap, we studied modulation of the phagocytic activity of human U118 MG astrocytic cells and murine primary astrocytes by four CNS inflammatory mediators and bacterial endotoxin lipopolysaccharide (LPS). LPS and cytochrome c (CytC) upregulated, while interferon (IFN)-γ downregulated, phagocytosis of latex beads by human astrocytic cells and phagocytosis of synaptosomes by murine primary astrocytes. Interleukin (IL)-1β and tumor necrosis factor (TNF)-α had no effect on the phagocytic activity of human astrocytic cells but upregulated this function in murine astrocytes. Varying effects of combinations of the above inflammatory mediators were observed in these two cell types. LPS- and CytC-induced phagocytic activity of human astrocytic cells was partially mediated by activation of toll-like receptor 4 (TLR4). By monitoring other functions of astrocytes, we concluded there were no correlations between the effects of the mediators studied on astrocyte phagocytic activity and their secretion of cytokines, cytotoxins, or glutamate. Our study identified four candidate CNS regulators of astrocyte phagocytic activity. Future investigation of molecular mechanisms behind this regulation could identify novel therapeutic targets allowing modulation of this astrocyte-mediated clearance mechanism in CNS pathologies.
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Affiliation(s)
- Sijie Shirley Yang
- Department of Biology, University of British Columbia Okanagan Campus, University Way, Kelowna, British Columbia, Canada
| | - Svetlana Simtchouk
- Department of Biology, University of British Columbia Okanagan Campus, University Way, Kelowna, British Columbia, Canada
| | - Julien Gibon
- Department of Biology, University of British Columbia Okanagan Campus, University Way, Kelowna, British Columbia, Canada
| | - Andis Klegeris
- Department of Biology, University of British Columbia Okanagan Campus, University Way, Kelowna, British Columbia, Canada
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17
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Cullen PF, Sun D. Astrocytes of the eye and optic nerve: heterogeneous populations with unique functions mediate axonal resilience and vulnerability to glaucoma. FRONTIERS IN OPHTHALMOLOGY 2023; 3:1217137. [PMID: 37829657 PMCID: PMC10569075 DOI: 10.3389/fopht.2023.1217137] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/14/2023]
Abstract
The role of glia, particularly astrocytes, in mediating the central nervous system's response to injury and neurodegenerative disease is an increasingly well studied topic. These cells perform myriad support functions under physiological conditions but undergo behavioral changes - collectively referred to as 'reactivity' - in response to the disruption of neuronal homeostasis from insults, including glaucoma. However, much remains unknown about how reactivity alters disease progression - both beneficially and detrimentally - and whether these changes can be therapeutically modulated to improve outcomes. Historically, the heterogeneity of astrocyte behavior has been insufficiently addressed under both physiological and pathological conditions, resulting in a fragmented and often contradictory understanding of their contributions to health and disease. Thanks to increased focus in recent years, we now know this heterogeneity encompasses both intrinsic variation in physiological function and insult-specific changes that vary between pathologies. Although previous studies demonstrate astrocytic alterations in glaucoma, both in human disease and animal models, generally these findings do not conclusively link astrocytes to causative roles in neuroprotection or degeneration, rather than a subsequent response. Efforts to bolster our understanding by drawing on knowledge of brain astrocytes has been constrained by the primacy in the literature of findings from peri-synaptic 'gray matter' astrocytes, whereas much early degeneration in glaucoma occurs in axonal regions populated by fibrous 'white matter' astrocytes. However, by focusing on findings from astrocytes of the anterior visual pathway - those of the retina, unmyelinated optic nerve head, and myelinated optic nerve regions - we aim to highlight aspects of their behavior that may contribute to axonal vulnerability and glaucoma progression, including roles in mitochondrial turnover and energy provisioning. Furthermore, we posit that astrocytes of the retina, optic nerve head and myelinated optic nerve, although sharing developmental origins and linked by a network of gap junctions, may be best understood as distinct populations residing in markedly different niches with accompanying functional specializations. A closer investigation of their behavioral repertoires may elucidate not only their role in glaucoma, but also mechanisms to induce protective behaviors that can impede the progressive axonal damage and retinal ganglion cell death that drive vision loss in this devastating condition.
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Affiliation(s)
- Paul F. Cullen
- Department of Ophthalmology, Schepens Eye Research Institute of Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, United States
| | - Daniel Sun
- Department of Ophthalmology, Schepens Eye Research Institute of Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, United States
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18
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Luis J, Eastlake K, Lamb WDB, Limb GA, Jayaram H, Khaw PT. Cell-Based Therapies for Glaucoma. Transl Vis Sci Technol 2023; 12:23. [PMID: 37494052 PMCID: PMC10383000 DOI: 10.1167/tvst.12.7.23] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 06/20/2023] [Indexed: 07/27/2023] Open
Abstract
Glaucomatous optic neuropathy (GON) is the major cause of irreversible visual loss worldwide and can result from a range of disease etiologies. The defining features of GON are retinal ganglion cell (RGC) degeneration and characteristic cupping of the optic nerve head (ONH) due to tissue remodeling, while intraocular pressure remains the only modifiable GON risk factor currently targeted by approved clinical treatment strategies. Efforts to understand the mechanisms that allow species such as the zebrafish to regenerate their retinal cells have greatly increased our understanding of regenerative signaling pathways. However, proper integration within the retina and projection to the brain by the newly regenerated neuronal cells remain major hurdles. Meanwhile, a range of methods for in vitro differentiation have been developed to derive retinal cells from a variety of cell sources, including embryonic and induced pluripotent stem cells. More recently, there has been growing interest in the implantation of glial cells as well as cell-derived products, including neurotrophins, microRNA, and extracellular vesicles, to provide functional support to vulnerable structures such as RGC axons and the ONH. These approaches offer the advantage of not relying upon the replacement of degenerated cells and potentially targeting earlier stages of disease pathogenesis. In order to translate these techniques into clinical practice, appropriate cell sourcing, robust differentiation protocols, and accurate implantation methods are crucial to the success of cell-based therapy in glaucoma. Translational Relevance: Cell-based therapies for glaucoma currently under active development include the induction of endogenous regeneration, implantation of exogenously derived retinal cells, and utilization of cell-derived products to provide functional support.
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Affiliation(s)
- Joshua Luis
- NIHR Biomedical Research Centre for Ophthalmology, UCL Institute of Ophthalmology & Moorfields Eye Hospital, London, UK
| | - Karen Eastlake
- NIHR Biomedical Research Centre for Ophthalmology, UCL Institute of Ophthalmology & Moorfields Eye Hospital, London, UK
| | - William D. B. Lamb
- NIHR Biomedical Research Centre for Ophthalmology, UCL Institute of Ophthalmology & Moorfields Eye Hospital, London, UK
| | - G. Astrid Limb
- NIHR Biomedical Research Centre for Ophthalmology, UCL Institute of Ophthalmology & Moorfields Eye Hospital, London, UK
| | - Hari Jayaram
- NIHR Biomedical Research Centre for Ophthalmology, UCL Institute of Ophthalmology & Moorfields Eye Hospital, London, UK
| | - Peng T. Khaw
- NIHR Biomedical Research Centre for Ophthalmology, UCL Institute of Ophthalmology & Moorfields Eye Hospital, London, UK
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Wan Y, Wang H, Fan X, Bao J, Wu S, Liu Q, Yan X, Zhang J, Jin ZB, Xiao B, Wang N. Mechanosensitive channel Piezo1 is an essential regulator in cell cycle progression of optic nerve head astrocytes. Glia 2023; 71:1233-1246. [PMID: 36598105 DOI: 10.1002/glia.24334] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 12/23/2022] [Accepted: 12/26/2022] [Indexed: 01/05/2023]
Abstract
Optic nerve head (ONH) astrocytes provide structural and metabolic support to neuronal axons in developmental, physiological, and pathological progression. Mechanosensitive properties of astrocytes allow them to sense and respond to mechanical cues from the local environment. We confirmed that ONH astrocytes express the mechanosensitive ion channel Piezo1 in vivo. By manipulating Piezo1 knockdown or overexpression in vitro, we found that Piezo1 is necessary but insufficient for ONH astrocyte proliferation. Loss of Piezo1 can lead to cell cycle arrest at G0/G1 phase, a possible mechanism involving decreased yes-associated protein (YAP) nuclear localization and downregulation of YAP-target cell cycle-associated factors, including cyclin D1 and c-Myc. Gene ontology enrichment analysis of differential expression genes from RNA-seq data indicates that the absence of Piezo1 affects biological processes involving cell division. Our results demonstrate that Piezo1 is an essential regulator in cell cycle progression in ONH astrocytes.
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Affiliation(s)
- Yue Wan
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Beijing Ophthalmology & Visual Sciences Key Laboratory, Capital Medical University, Beijing, China
| | - Haiping Wang
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, IDG/McGovern Institute for Brain Research, Beijing Frontier Research Center for Biological Structure, Beijing Advanced Innovation Center for Structural Biology, School of Pharmaceutical Sciences, Tsinghua University, Beijing, China
| | - Xiaowei Fan
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Beijing Ophthalmology & Visual Sciences Key Laboratory, Capital Medical University, Beijing, China
| | - Jiayu Bao
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Beijing Ophthalmology & Visual Sciences Key Laboratory, Capital Medical University, Beijing, China
| | - Shen Wu
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Beijing Ophthalmology & Visual Sciences Key Laboratory, Capital Medical University, Beijing, China
| | - Qian Liu
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Beijing Ophthalmology & Visual Sciences Key Laboratory, Capital Medical University, Beijing, China
| | - Xuejing Yan
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Beijing Ophthalmology & Visual Sciences Key Laboratory, Capital Medical University, Beijing, China
| | - Jingxue Zhang
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Beijing Ophthalmology & Visual Sciences Key Laboratory, Capital Medical University, Beijing, China
| | - Zi-Bing Jin
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Beijing Ophthalmology & Visual Sciences Key Laboratory, Capital Medical University, Beijing, China
| | - Bailong Xiao
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, IDG/McGovern Institute for Brain Research, Beijing Frontier Research Center for Biological Structure, Beijing Advanced Innovation Center for Structural Biology, School of Pharmaceutical Sciences, Tsinghua University, Beijing, China
| | - Ningli Wang
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Beijing Ophthalmology & Visual Sciences Key Laboratory, Capital Medical University, Beijing, China
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20
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Lemus Silva EG, Delgadillo Y, White RE, Lucin KM. Beclin 1 regulates astrocyte phagocytosis and phagosomal recruitment of retromer. Tissue Cell 2023; 82:102100. [PMID: 37182392 DOI: 10.1016/j.tice.2023.102100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 04/21/2023] [Accepted: 04/26/2023] [Indexed: 05/16/2023]
Abstract
Phagocytosis plays an important role in maintaining brain homeostasis and when impaired can result in the accumulation of unwanted cellular material. While microglia are traditionally considered the phagocytes of the brain, astrocytes are also capable of phagocytosis and are the most numerous cells in the brain. In Alzheimer's disease (AD), astrocytes can be found surrounding β-amyloid (Aβ) plaques yet they seem unable to eliminate these deposits, suggesting phagocytosis may be impaired in AD. Mechanisms that might diminish astrocyte phagocytosis in AD are currently unclear. Here, we demonstrate that the autophagy protein beclin 1, which is reduced in AD, plays a role in regulating astrocyte phagocytosis. Specifically, we show that reducing beclin 1 in C6 astrocytes impairs the phagocytosis of latex beads, reduces retromer levels, and impairs retromer recruitment to the phagosomal membrane. Furthermore, we show that these beclin 1-mediated changes are accompanied by reduced expression of the phagocytic receptor Scavenger Receptor Class B type I (SR-BI). Collectively, these findings suggest a critical role for the protein beclin 1 in both receptor trafficking and receptor-mediated phagocytosis in astrocytes. Moreover, these findings provide insight into mechanisms by which astrocytes may become impaired in AD.
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Affiliation(s)
| | | | - Robin E White
- Westfield State University, Westfield, MA 01086, USA
| | - Kurt M Lucin
- Eastern Connecticut State University, Willimantic, CT 06226, USA.
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21
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Miao Y, Zhao GL, Cheng S, Wang Z, Yang XL. Activation of retinal glial cells contributes to the degeneration of ganglion cells in experimental glaucoma. Prog Retin Eye Res 2023; 93:101169. [PMID: 36736070 DOI: 10.1016/j.preteyeres.2023.101169] [Citation(s) in RCA: 44] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 01/12/2023] [Accepted: 01/24/2023] [Indexed: 02/04/2023]
Abstract
Elevation of intraocular pressure (IOP) is a major risk factor for neurodegeneration in glaucoma. Glial cells, which play an important role in normal functioning of retinal neurons, are well involved into retinal ganglion cell (RGC) degeneration in experimental glaucoma animal models generated by elevated IOP. In response to elevated IOP, mGluR I is first activated and Kir4.1 channels are subsequently inhibited, which leads to the activation of Müller cells. Müller cell activation is followed by a complex process, including proliferation, release of inflammatory and growth factors (gliosis). Gliosis is further regulated by several factors. Activated Müller cells contribute to RGC degeneration through generating glutamate receptor-mediated excitotoxicity, releasing cytotoxic factors and inducing microglia activation. Elevated IOP activates microglia, and following morphological and functional changes, these cells, as resident immune cells in the retina, show adaptive immune responses, including an enhanced release of pro-inflammatory factors (tumor neurosis factor-α, interleukins, etc.). These ATP and Toll-like receptor-mediated responses are further regulated by heat shock proteins, CD200R, chemokine receptors, and metabotropic purinergic receptors, may aggravate RGC loss. In the optic nerve head, astrogliosis is initiated and regulated by a complex reaction process, including purines, transmitters, chemokines, growth factors and cytokines, which contributes to RGC axon injury through releasing pro-inflammatory factors and changing extracellular matrix in glaucoma. The effects of activated glial cells on RGCs are further modified by the interplay among different types of glial cells. This review is concluded by presenting an in-depth discussion of possible research directions in this field in the future.
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Affiliation(s)
- Yanying Miao
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, 200032, China
| | - Guo-Li Zhao
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, 200032, China
| | - Shuo Cheng
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, 200032, China
| | - Zhongfeng Wang
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, 200032, China.
| | - Xiong-Li Yang
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, 200032, China.
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22
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Nadal-Nicolás FM, Galindo-Romero C, Lucas-Ruiz F, Marsh-Amstrong N, Li W, Vidal-Sanz M, Agudo-Barriuso M. Pan-retinal ganglion cell markers in mice, rats, and rhesus macaques. Zool Res 2023; 44:226-248. [PMID: 36594396 PMCID: PMC9841181 DOI: 10.24272/j.issn.2095-8137.2022.308] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022] Open
Abstract
Univocal identification of retinal ganglion cells (RGCs) is an essential prerequisite for studying their degeneration and neuroprotection. Before the advent of phenotypic markers, RGCs were normally identified using retrograde tracing of retinorecipient areas. This is an invasive technique, and its use is precluded in higher mammals such as monkeys. In the past decade, several RGC markers have been described. Here, we reviewed and analyzed the specificity of nine markers used to identify all or most RGCs, i.e., pan-RGC markers, in rats, mice, and macaques. The best markers in the three species in terms of specificity, proportion of RGCs labeled, and indicators of viability were BRN3A, expressed by vision-forming RGCs, and RBPMS, expressed by vision- and non-vision-forming RGCs. NEUN, often used to identify RGCs, was expressed by non-RGCs in the ganglion cell layer, and therefore was not RGC-specific. γ-SYN, TUJ1, and NF-L labeled the RGC axons, which impaired the detection of their somas in the central retina but would be good for studying RGC morphology. In rats, TUJ1 and NF-L were also expressed by non-RGCs. BM88, ERRβ, and PGP9.5 are rarely used as markers, but they identified most RGCs in the rats and macaques and ERRβ in mice. However, PGP9.5 was also expressed by non-RGCs in rats and macaques and BM88 and ERRβ were not suitable markers of viability.
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Affiliation(s)
- Francisco M Nadal-Nicolás
- Grupo de Oftalmología Experimental, Instituto Murciano de Investigación Biosanitaria Pascual Parrilla (IMIB), Murcia 30120, Spain
- Dpto. Oftalmología, Facultad de Medicina, Universidad de Murcia, Murcia 30120, Spain
- Retinal Neurophysiology Section, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892-2510, USA
| | - Caridad Galindo-Romero
- Grupo de Oftalmología Experimental, Instituto Murciano de Investigación Biosanitaria Pascual Parrilla (IMIB), Murcia 30120, Spain
- Dpto. Oftalmología, Facultad de Medicina, Universidad de Murcia, Murcia 30120, Spain
| | - Fernando Lucas-Ruiz
- Grupo de Oftalmología Experimental, Instituto Murciano de Investigación Biosanitaria Pascual Parrilla (IMIB), Murcia 30120, Spain
- Dpto. Oftalmología, Facultad de Medicina, Universidad de Murcia, Murcia 30120, Spain
| | - Nicholas Marsh-Amstrong
- Department of Ophthalmology and Vision Science, University of California, Davis, CA 95817, USA
| | - Wei Li
- Retinal Neurophysiology Section, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892-2510, USA
| | - Manuel Vidal-Sanz
- Grupo de Oftalmología Experimental, Instituto Murciano de Investigación Biosanitaria Pascual Parrilla (IMIB), Murcia 30120, Spain
- Dpto. Oftalmología, Facultad de Medicina, Universidad de Murcia, Murcia 30120, Spain. E-mail:
| | - Marta Agudo-Barriuso
- Grupo de Oftalmología Experimental, Instituto Murciano de Investigación Biosanitaria Pascual Parrilla (IMIB), Murcia 30120, Spain
- Dpto. Oftalmología, Facultad de Medicina, Universidad de Murcia, Murcia 30120, Spain. E-mail:
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23
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Reinehr S, Girbig RM, Schulte KK, Theile J, Asaad MA, Fuchshofer R, Dick H, Joachim SC. Enhanced glaucomatous damage accompanied by glial response in a new multifactorial mouse model. Front Immunol 2023; 13:1017076. [PMID: 36733392 PMCID: PMC9887307 DOI: 10.3389/fimmu.2022.1017076] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 12/19/2022] [Indexed: 01/18/2023] Open
Abstract
Introduction Glaucoma is a complex, multifactorial neurodegenerative disease, which can lead to blindness if left untreated. It seems that, among others, immune processes, elevated intraocular pressure (IOP), or a combination of these factors are responsible for glaucomatous damage. Here, we combined two glaucoma models to examine if a combination of risk factors (IOP and immune response) results in a more severe damage of retinal ganglion cells (RGCs) and the optic nerves as well as an additional glia activation. Methods Six-week-old wildtype (WT+ONA) and βB1-Connective Tissue Growth Factor (CTGF) mice (CTGF+ONA) were immunized with 1 mg ONA (optic nerve antigen). A WT and a CTGF control group (CTGF) received sodium chloride instead. IOP was measured before and every two weeks after immunization. After six weeks, electroretinogram (ERG) measurements were performed. Then, retinae and optic nerves were processed for (immuno-) histology. Further, mRNA levels of corresponding genes in optic nerve and retina were analyzed via RT-qPCR. Results Six weeks after immunization, the IOP in CTGF and CTGF+ONA mice was increased. The optic nerve of CTGF+ONA animals displayed the most severe cell inflammation, demyelination, and macroglia activation. Fewer numbers of oligodendrocytes were only observed in WT+ONA optic nerves, while more apoptotic cells triggered by the extrinsic pathway could be revealed in all three glaucoma groups. The number of microglia/macrophages was not altered within the optic nerves of all groups. The loss of neuronal cells, especially RGCs was most pronounced in CTGF+ONA retinae in the central part and this was accompanied by an enhanced activation of microglia/macrophages. Also, Müller cell activation could be noted in CTGF and CTGF+ONA retinae. Discussion In this new model, an additive degeneration could be noted in optic nerves as well as in the number of RGCs. These results suggest a potential additive role of high IOP and immune factors in glaucoma development, which will aid for understanding this multifactorial disease more precisely in the future.
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Affiliation(s)
- Sabrina Reinehr
- Experimental Eye Research Institute, University Eye Hospital, Ruhr-University Bochum, Bochum, Germany,*Correspondence: Sabrina Reinehr,
| | - Renée M. Girbig
- Experimental Eye Research Institute, University Eye Hospital, Ruhr-University Bochum, Bochum, Germany
| | - Kim K. Schulte
- Experimental Eye Research Institute, University Eye Hospital, Ruhr-University Bochum, Bochum, Germany
| | - Janine Theile
- Experimental Eye Research Institute, University Eye Hospital, Ruhr-University Bochum, Bochum, Germany
| | - M. Ali Asaad
- Experimental Eye Research Institute, University Eye Hospital, Ruhr-University Bochum, Bochum, Germany
| | - Rudolf Fuchshofer
- Institute of Human Anatomy and Embryology, University Regensburg, Regensburg, Germany
| | - H. Burkhard Dick
- Experimental Eye Research Institute, University Eye Hospital, Ruhr-University Bochum, Bochum, Germany
| | - Stephanie C. Joachim
- Experimental Eye Research Institute, University Eye Hospital, Ruhr-University Bochum, Bochum, Germany
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24
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Dias SB, de Lemos L, Sousa L, Bitoque DB, Silva GA, Seabra MC, Tenreiro S. Age-Related Changes of the Synucleins Profile in the Mouse Retina. Biomolecules 2023; 13:biom13010180. [PMID: 36671565 PMCID: PMC9855780 DOI: 10.3390/biom13010180] [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: 11/10/2022] [Revised: 12/28/2022] [Accepted: 01/11/2023] [Indexed: 01/18/2023] Open
Abstract
Alpha-synuclein (aSyn) plays a central role in Parkinson's disease (PD) and has been extensively studied in the brain. This protein is part of the synuclein family, which is also composed of beta-synuclein (bSyn) and gamma-synuclein (gSyn). In addition to its neurotoxic role, synucleins have important functions in the nervous system, modulating synaptic transmission. Synucleins are expressed in the retina, but they have been poorly characterized. However, there is evidence that they are important for visual function and that they can play a role in retinal degeneration. This study aimed to profile synucleins in the retina of naturally aged mice and to correlate their patterns with specific retinal cells. With aging, we observed a decrease in the thickness of specific retinal layers, accompanied by an increase in glial reactivity. Moreover, the aSyn levels decreased, whereas bSyn increased with aging. The colocalization of both proteins was decreased in the inner plexiform layer (IPL) of the aged retina. gSyn presented an age-related decrease at the inner nuclear layer but was not significantly changed in the ganglion cell layer. The synaptic marker synaptophysin was shown to be preferentially colocalized with aSyn in the IPL with aging. At the same time, aSyn was found to exist at the presynaptic endings of bipolar cells and was affected by aging. Overall, this study suggests that physiological aging can be responsible for changes in the retinal tissue, implicating functional alterations that could affect synuclein family function.
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Affiliation(s)
- Sarah Batista Dias
- iNOVA4Health, NOVA Medical School|Faculdade de Ciências Médicas, NMS|FCM, Universidade Nova de Lisboa, 1169-056 Lisboa, Portugal
| | - Luísa de Lemos
- iNOVA4Health, NOVA Medical School|Faculdade de Ciências Médicas, NMS|FCM, Universidade Nova de Lisboa, 1169-056 Lisboa, Portugal
| | - Luís Sousa
- iNOVA4Health, NOVA Medical School|Faculdade de Ciências Médicas, NMS|FCM, Universidade Nova de Lisboa, 1169-056 Lisboa, Portugal
| | - Diogo B. Bitoque
- iNOVA4Health, NOVA Medical School|Faculdade de Ciências Médicas, NMS|FCM, Universidade Nova de Lisboa, 1169-056 Lisboa, Portugal
| | - Gabriela Araújo Silva
- iNOVA4Health, NOVA Medical School|Faculdade de Ciências Médicas, NMS|FCM, Universidade Nova de Lisboa, 1169-056 Lisboa, Portugal
| | - Miguel C. Seabra
- iNOVA4Health, NOVA Medical School|Faculdade de Ciências Médicas, NMS|FCM, Universidade Nova de Lisboa, 1169-056 Lisboa, Portugal
- UCL Institute of Ophthalmology, London EC1V 9EL, UK
| | - Sandra Tenreiro
- iNOVA4Health, NOVA Medical School|Faculdade de Ciências Médicas, NMS|FCM, Universidade Nova de Lisboa, 1169-056 Lisboa, Portugal
- Correspondence:
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25
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Li S, Jakobs TC. Secreted phosphoprotein 1 slows neurodegeneration and rescues visual function in mouse models of aging and glaucoma. Cell Rep 2022; 41:111880. [PMID: 36577373 PMCID: PMC9847489 DOI: 10.1016/j.celrep.2022.111880] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 11/01/2022] [Accepted: 12/02/2022] [Indexed: 12/29/2022] Open
Abstract
Aging causes an irreversible, cumulative decline in neuronal function. Using the visual system as a model, we show that astrocytes play a critical role in maintaining retinal ganglion cell health and that deletion of SPP1 (secreted phosphoprotein 1, or osteopontin) from astrocytes leads to increased vulnerability of ganglion cells to age, elevated intraocular pressure, and traumatic optic nerve damage. Overexpression of SPP1 slows the age-related decline in ganglion cell numbers and is highly protective of visual function in a mouse model of glaucoma. SPP1 acts by promoting phagocytosis and secretion of neurotrophic factors while inhibiting production of neurotoxic and pro-inflammatory factors. SPP1 up-regulates transcription of genes related to oxidative phosphorylation, functionally enhances mitochondrial respiration, and promotes the integrity of mitochondrial microstructure. SPP1 increases intracellular ATP concentration via up-regulation of VDAC1.
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Affiliation(s)
- Song Li
- Department of Ophthalmology, Harvard Medical School, Boston, MA 02114, USA; Schepens Eye Research Institute, Massachusetts Eye and Ear, Boston, MA 02114, USA.
| | - Tatjana C Jakobs
- Department of Ophthalmology, Harvard Medical School, Boston, MA 02114, USA; Schepens Eye Research Institute, Massachusetts Eye and Ear, Boston, MA 02114, USA.
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Lambuk L, Suhaimi NAA, Sadikan MZ, Jafri AJA, Ahmad S, Nasir NAA, Uskoković V, Kadir R, Mohamud R. Nanoparticles for the treatment of glaucoma-associated neuroinflammation. EYE AND VISION 2022; 9:26. [PMID: 35778750 PMCID: PMC9250254 DOI: 10.1186/s40662-022-00298-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Accepted: 06/09/2022] [Indexed: 12/03/2022]
Abstract
Recently, a considerable amount of literature has emerged around the theme of neuroinflammation linked to neurodegeneration. Glaucoma is a neurodegenerative disease characterized by visual impairment. Understanding the complex neuroinflammatory processes underlying retinal ganglion cell loss has the potential to improve conventional therapeutic approaches in glaucoma. Due to the presence of multiple barriers that a systemically administered drug has to cross to reach the intraocular space, ocular drug delivery has always been a challenge. Nowadays, studies are focused on improving the current therapies for glaucoma by utilizing nanoparticles as the modes of drug transport across the ocular anatomical and physiological barriers. This review offers some important insights on the therapeutic advancements made in this direction, focusing on the use of nanoparticles loaded with anti-inflammatory and neuroprotective agents in the treatment of glaucoma. The prospect of these novel therapies is discussed in relation to the current therapies to alleviate inflammation in glaucoma, which are being reviewed as well, along with the detailed molecular and cellular mechanisms governing the onset and the progression of the disease.
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27
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Tang Y, Chen Y, Chen D. The heterogeneity of astrocytes in glaucoma. Front Neuroanat 2022; 16:995369. [PMID: 36466782 PMCID: PMC9714578 DOI: 10.3389/fnana.2022.995369] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 10/31/2022] [Indexed: 09/10/2023] Open
Abstract
Glaucoma is a leading cause of blindness with progressive degeneration of retinal ganglion cells. Aging and increased intraocular pressure (IOP) are major risk factors. Lowering IOP does not always stop the disease progression. Alternative ways of protecting the optic nerve are intensively studied in glaucoma. Astrocytes are macroglia residing in the retina, optic nerve head (ONH), and visual brain, which keep neuronal homeostasis, regulate neuronal activities and are part of the immune responses to the retina and brain insults. In this brief review, we discuss the activation and heterogeneity of astrocytes in the retina, optic nerve head, and visual brain of glaucoma patients and animal models. We also discuss some recent transgenic and gene knockout studies using glaucoma mouse models to clarify the role of astrocytes in the pathogenesis of glaucoma. Astrocytes are heterogeneous and play crucial roles in the pathogenesis of glaucoma, especially in the process of neuroinflammation and mitochondrial dysfunction. In astrocytes, overexpression of Stat3 or knockdown of IκKβ/p65, caspase-8, and mitochondrial uncoupling proteins (Ucp2) can reduce ganglion cell loss in glaucoma mouse models. Based on these studies, therapeutic strategies targeting the heterogeneity of reactive astrocytes by enhancing their beneficial reactivity or suppressing their detrimental reactivity are alternative options for glaucoma treatment in the future.
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Affiliation(s)
- Yunjing Tang
- Research Laboratory of Ophthalmology and Vision Sciences, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, China
| | - Yongjiang Chen
- The School of Optometry and Vision Science, University of Waterloo, Waterloo, ON, Canada
| | - Danian Chen
- Research Laboratory of Ophthalmology and Vision Sciences, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, China
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28
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Rotshenker S. Galectin-3 (MAC-2) controls phagocytosis and macropinocytosis through intracellular and extracellular mechanisms. Front Cell Neurosci 2022; 16:949079. [PMID: 36274989 PMCID: PMC9581057 DOI: 10.3389/fncel.2022.949079] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 09/05/2022] [Indexed: 11/29/2022] Open
Abstract
Galectin-3 (Gal-3; formally named MAC-2) is a β-galactoside-binding lectin. Various cell types produce Gal-3 under either normal conditions and/or pathological conditions. Gal-3 can be present in cells' nuclei and cytoplasm, secreted from producing cells, and associated with cells' plasma membranes. This review focuses on how Gal-3 controls phagocytosis and macropinocytosis. Intracellular and extracellular Gal-3 promotes the phagocytosis of phagocytic targets/cargo (e.g., tissue debris and apoptotic cells) in “professional phagocytes” (e.g., microglia and macrophages) and “non-professional phagocytes” (e.g., Schwann cells and astrocytes). Intracellularly, Gal-3 promotes phagocytosis by controlling the “eat me” signaling pathways that phagocytic receptors generate, directing the cytoskeleton to produce the mechanical forces that drive the structural changes on which phagocytosis depends, protrusion and then retraction of filopodia and lamellipodia as they, respectively, engulf and then internalize phagocytic targets. Extracellularly, Gal-3 promotes phagocytosis by functioning as an opsonin, linking phagocytic targets to phagocytic receptors, activating them to generate the “eat me” signaling pathways. Macropinocytosis is a non-selective endocytic mechanism that various cells use to internalize the bulk of extracellular fluid and included materials/cargo (e.g., dissolved nutrients, proteins, and pathogens). Extracellular and intracellular Gal-3 control macropinocytosis in some types of cancer. Phagocytosed and macropinocytosed targets/cargo that reach lysosomes for degradation may rupture lysosomal membranes. Damaged lysosomal membranes undergo either repair or removal by selective autophagy (i.e., lysophagy) that intracellular Gal-3 controls.
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Chaudhary P, Stowell C, Reynaud J, Gardiner SK, Yang H, Williams G, Williams I, Marsh-Armstrong N, Burgoyne CF. Optic Nerve Head Myelin-Related Protein, GFAP, and Iba1 Alterations in Non-Human Primates With Early to Moderate Experimental Glaucoma. Invest Ophthalmol Vis Sci 2022; 63:9. [PMID: 36239974 PMCID: PMC9586137 DOI: 10.1167/iovs.63.11.9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Purpose The purpose of this study was to test if optic nerve head (ONH) myelin basic protein (MBP), 2′,3′-cyclic nucleotide 3′-phosphodiesterase (CNPase), glial fibrillary acidic protein (GFAP), and ionized calcium binding adaptor molecule 1 (Iba1) proteins are altered in non-human primate (NHP) early/moderate experimental glaucoma (EG). Methods Following paraformaldehyde perfusion, control and EG eye ONH tissues from four NHPs were paraffin embedded and serially (5 µm) vertically sectioned. Anti-MBP, CNPase, GFAP, Iba1, and nuclear dye-stained sections were imaged using sub-saturating light intensities. Whole-section images were segmented creating anatomically consistent laminar (L) and retrolaminar (RL) regions/sub-regions. EG versus control eye intensity/pixel-cluster density data within L and two RL regions (RL1 [1-250 µm]/RL2 [251-500 µm] from L) were compared using random effects models within the statistical program “R.” Results EG eye retinal nerve fiber loss ranged from 0% to 20%. EG eyes’ MBP and CNPase intensity were decreased within the RL1 (MBP = 31.4%, P < 0.001; CNPase =62.3%, P < 0.001) and RL2 (MBP = 19.6%, P < 0.001; CNPase = 56.1%, P = 0.0004) regions. EG eye GFAP intensity was decreased in the L (41.6%, P < 0.001) and RL regions (26.7% for RL1, and 28.4% for RL2, both P < 0.001). Iba1+ and NucBlue pixel-cluster density were increased in the laminar (28.2%, P = 0.03 and 16.6%, P = 0.008) and both RL regions (RL1 = 37.3%, P = 0.01 and 23.7%, P = 0.0002; RL2 = 53.7%, P = 0.002 and 33.2%, P < 0.001). Conclusions Retrolaminar myelin disruption occurs early in NHP EG and may be accompanied by laminar and retrolaminar decreases in astrocyte process labeling and increases in microglial/ macrophage density. The mechanistic and therapeutic implications of these findings warrant further study.
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Affiliation(s)
- Priya Chaudhary
- Optic Nerve Head Research Laboratory, Devers Eye Institute, Legacy Research Institute, Portland, Oregon, United States.,Discoveries in Sight, Devers Eye Institute, Legacy Research Institute, Portland, Oregon, United States
| | - Cheri Stowell
- Optic Nerve Head Research Laboratory, Devers Eye Institute, Legacy Research Institute, Portland, Oregon, United States.,Discoveries in Sight, Devers Eye Institute, Legacy Research Institute, Portland, Oregon, United States
| | - Juan Reynaud
- Optic Nerve Head Research Laboratory, Devers Eye Institute, Legacy Research Institute, Portland, Oregon, United States.,Discoveries in Sight, Devers Eye Institute, Legacy Research Institute, Portland, Oregon, United States
| | - Stuart K Gardiner
- Discoveries in Sight, Devers Eye Institute, Legacy Research Institute, Portland, Oregon, United States
| | - Hongli Yang
- Optic Nerve Head Research Laboratory, Devers Eye Institute, Legacy Research Institute, Portland, Oregon, United States.,Discoveries in Sight, Devers Eye Institute, Legacy Research Institute, Portland, Oregon, United States
| | - Galen Williams
- Optic Nerve Head Research Laboratory, Devers Eye Institute, Legacy Research Institute, Portland, Oregon, United States.,Discoveries in Sight, Devers Eye Institute, Legacy Research Institute, Portland, Oregon, United States
| | - Imee Williams
- Optic Nerve Head Research Laboratory, Devers Eye Institute, Legacy Research Institute, Portland, Oregon, United States.,Discoveries in Sight, Devers Eye Institute, Legacy Research Institute, Portland, Oregon, United States
| | | | - Claude F Burgoyne
- Optic Nerve Head Research Laboratory, Devers Eye Institute, Legacy Research Institute, Portland, Oregon, United States.,Discoveries in Sight, Devers Eye Institute, Legacy Research Institute, Portland, Oregon, United States
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30
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Lai W, Huang J, Fang W, Deng S, Xie Y, Wang W, Qiao T, Xu G, Wang X, Ding F. Optic nerve head: A gatekeeper for vitreous infectious insults? Front Immunol 2022; 13:987771. [PMID: 36203577 PMCID: PMC9531234 DOI: 10.3389/fimmu.2022.987771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 08/31/2022] [Indexed: 11/19/2022] Open
Abstract
The axons of retinal ganglion cells (RGCs) pass through the optic nerve head (ONH) and form the optic nerve (ON). The ONH serves as an anatomical interface between the vitreous cavity and subarachnoid space. After inducing acute neuroinflammation by intravitreal injection of lipopolysaccharides (LPS), we observed inflammatory activation in the retina, but detect no signs of inflammation in the posterior ON or infiltration of inflammatory cells in the ONH. Therefore, we hypothesized that the ONH functions as a barrier to vitreous inflammation. Using transmission electron microscopy, we identified significant increase in G-ratio in the posterior ON on day 7 post intravitreal injection (PII) of LPS compared with the phosphate buffered saline (PBS) group. Moreover, using confocal imaging of ex vivo tissue extracted from Aldh1L1-eGFP reporter mice, we observed that the ONH astrocytes altered their spatial orientation by elongating their morphology along the axonal axis of RGCs in LPS- versus PBS-treated eyes; this was quantified by the ratio of longitudinal (DL) and transverse (DT) diameter of astrocytes and the proportion of longitudinally locating astrocytes. Supportive evidences were further provided by transmission electron microscopic imaging in rat ONH. We further conducted RNA sequencing of ONH on day 1 PII and found LPS induced clear upregulation of immune and inflammatory pathways. Furthermore, gene set enrichment analysis revealed that astrocyte and microglia contributed prominently to the transcriptomic alterations in ONH. Here, we report that the vitreous infectious insults induce morphological changes of ONH astrocytes and transcriptomic alterations in the ONH. Glial responses in the ONH may defend against vitreous infectious insults and serve as a barrier to inflammation for the central nervous system.
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Affiliation(s)
- Wenwen Lai
- Department of Pharmacology, School of Basic Medical Sciences; Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Fudan University, Shanghai, China
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jie Huang
- Department of Pharmacology, School of Basic Medical Sciences; Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Fudan University, Shanghai, China
- Department of Ophthalmology, Eye, Ear, Nose and Throat Hospital; State Key Laboratory of Medical Neurobiology and Ministry of Education Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Wangyi Fang
- Department of Ophthalmology, Shanghai Children’s Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Saiyue Deng
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yi Xie
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Wei Wang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Tong Qiao
- Department of Ophthalmology, Shanghai Children’s Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Gezhi Xu
- Department of Pharmacology, School of Basic Medical Sciences; Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Fudan University, Shanghai, China
- Department of Ophthalmology, Eye, Ear, Nose and Throat Hospital; State Key Laboratory of Medical Neurobiology and Ministry of Education Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Xiaowei Wang
- Department of Ophthalmology, University of California San Francisco, San Francisco, CA, United States
- *Correspondence: Fengfei Ding, ; Xiaowei Wang,
| | - Fengfei Ding
- Department of Pharmacology, School of Basic Medical Sciences; Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Fudan University, Shanghai, China
- Department of Ophthalmology, Eye, Ear, Nose and Throat Hospital; State Key Laboratory of Medical Neurobiology and Ministry of Education Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
- *Correspondence: Fengfei Ding, ; Xiaowei Wang,
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31
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Zou D, Qin J, Hu W, Wei Z, Zhan Y, He Y, Zhao C, Li L. Macrophages Rapidly Seal off the Punctured Zebrafish Larval Brain through a Vital Honeycomb Network Structure. Int J Mol Sci 2022; 23:ijms231810551. [PMID: 36142462 PMCID: PMC9503817 DOI: 10.3390/ijms231810551] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 08/30/2022] [Accepted: 09/07/2022] [Indexed: 11/26/2022] Open
Abstract
There is accumulating evidence that macrophages play additional important roles in tissue damage besides their typical phagocytosis. Although the aggregation of macrophages on injured sites has long been observed, few researchers have focused on the role of the overall structure of macrophage aggregation. In this study, we developed a standardized traumatic brain injury (TBI) model in zebrafish larvae to mimic edema and brain tissue spillage symptoms after severe brain trauma. Using time-lapse imaging, we showed that macrophages/microglia in zebrafish larvae responded rapidly and dominated the surface of injured tissue, forming a meaningful honeycomb network structure through their compact aggregation and connection. Disrupting this structure led to fatal edema-like symptoms with severe loss of brain tissue. Using the RNA-Seq, together with the manipulation of in vitro cell lines, we found that collagen IV was indispensable to the formation of honeycomb network structures. Our study thus revealed a novel perspective regarding macrophages forming a protective compact structure with collagen IV. This honeycomb network structure acted as a physical barrier to prevent tissue loss and maintain brain homeostasis after TBI. This study may provide new evidence of macrophages’ function for the rapid protection of brain tissue after brain injury.
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Affiliation(s)
- Dandan Zou
- Key Laboratory of Freshwater Fish Reproduction and Development, Ministry of Education, Institute of Developmental Biology and Regenerative Medicine, Southwest University, Beibei, Chongqing 400715, China
| | - Jie Qin
- Key Laboratory of Freshwater Fish Reproduction and Development, Ministry of Education, Institute of Developmental Biology and Regenerative Medicine, Southwest University, Beibei, Chongqing 400715, China
| | - Wenlong Hu
- Key Laboratory of Freshwater Fish Reproduction and Development, Ministry of Education, Institute of Developmental Biology and Regenerative Medicine, Southwest University, Beibei, Chongqing 400715, China
| | - Zongfang Wei
- Key Laboratory of Freshwater Fish Reproduction and Development, Ministry of Education, Institute of Developmental Biology and Regenerative Medicine, Southwest University, Beibei, Chongqing 400715, China
| | - Yandong Zhan
- Key Laboratory of Freshwater Fish Reproduction and Development, Ministry of Education, Institute of Developmental Biology and Regenerative Medicine, Southwest University, Beibei, Chongqing 400715, China
| | - Yuepeng He
- Key Laboratory of Freshwater Fish Reproduction and Development, Ministry of Education, Institute of Developmental Biology and Regenerative Medicine, Southwest University, Beibei, Chongqing 400715, China
| | - Congjian Zhao
- Chongqing Engineering Research Center of Medical Electronics and Information Technology, School of Biomedical Engineering and Informatics, Chongqing University of Posts and Telecommunications, Chongqing 400065, China
| | - Li Li
- Research Center of Stem Cells and Ageing, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
- Correspondence:
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Inaba M, Ridwan SM, Antel M. Removal of cellular protrusions. Semin Cell Dev Biol 2022; 129:126-134. [PMID: 35260295 PMCID: PMC9378436 DOI: 10.1016/j.semcdb.2022.02.025] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 02/24/2022] [Accepted: 02/25/2022] [Indexed: 02/08/2023]
Abstract
Cell-cell communications are central to a variety of physiological and pathological processes in multicellular organisms. Cells often rely on cellular protrusions to communicate with one another, which enable highly selective and efficient signaling within complex tissues. Owing to significant improvements in imaging techniques, identification of signaling protrusions has increased in recent years. These protrusions are structurally specialized for signaling and facilitate interactions between cells. Therefore, physical regulation of these structures must be key for the appropriate strength and pattern of signaling outcomes. However, the typical approaches for understanding signaling regulation tend to focus solely on changes in signaling molecules, such as gene expression, protein-protein interaction, and degradation. In this short review, we summarize the studies proposing the removal of different types of signaling protrusions-including cilia, neurites, MT (microtubule based)-nanotubes and microvilli-and discuss their mechanisms and significance in signaling regulation.
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Affiliation(s)
- Mayu Inaba
- Department of Cell Biology, University of Connecticut Health Center, Farmington, CT 06030, USA.
| | - Sharif M Ridwan
- Department of Cell Biology, University of Connecticut Health Center, Farmington, CT 06030, USA
| | - Matthew Antel
- Department of Cell Biology, University of Connecticut Health Center, Farmington, CT 06030, USA
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Ulamec SM, Maya-Martinez R, Byrd EJ, Dewison KM, Xu Y, Willis LF, Sobott F, Heath GR, van Oosten Hawle P, Buchman VL, Radford SE, Brockwell DJ. Single residue modulators of amyloid formation in the N-terminal P1-region of α-synuclein. Nat Commun 2022; 13:4986. [PMID: 36008493 PMCID: PMC9411612 DOI: 10.1038/s41467-022-32687-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 08/10/2022] [Indexed: 11/09/2022] Open
Abstract
Alpha-synuclein (αSyn) is a protein involved in neurodegenerative disorders including Parkinson's disease. Amyloid formation of αSyn can be modulated by the 'P1 region' (residues 36-42). Here, mutational studies of P1 reveal that Y39A and S42A extend the lag-phase of αSyn amyloid formation in vitro and rescue amyloid-associated cytotoxicity in C. elegans. Additionally, L38I αSyn forms amyloid fibrils more rapidly than WT, L38A has no effect, but L38M does not form amyloid fibrils in vitro and protects from proteotoxicity. Swapping the sequence of the two residues that differ in the P1 region of the paralogue γSyn to those of αSyn did not enhance fibril formation for γSyn. Peptide binding experiments using NMR showed that P1 synergises with residues in the NAC and C-terminal regions to initiate aggregation. The remarkable specificity of the interactions that control αSyn amyloid formation, identifies this region as a potential target for therapeutics, despite their weak and transient nature.
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Affiliation(s)
- Sabine M Ulamec
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Roberto Maya-Martinez
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Emily J Byrd
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Katherine M Dewison
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Yong Xu
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Leon F Willis
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Frank Sobott
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - George R Heath
- Astbury Centre for Structural Molecular Biology, School of Physics & Astronomy, University of Leeds, Leeds, LS2 9JT, UK
| | - Patricija van Oosten Hawle
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Vladimir L Buchman
- School of Biosciences, Cardiff University, Cardiff, CF10 3AX, UK
- Belgorod State National Research University, 85 Pobedy Street, Belgorod, 308015, Belgorod Region, Russian Federation
| | - Sheena E Radford
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK.
| | - David J Brockwell
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK.
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34
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Strickland RG, Garner MA, Gross AK, Girkin CA. Remodeling of the Lamina Cribrosa: Mechanisms and Potential Therapeutic Approaches for Glaucoma. Int J Mol Sci 2022; 23:8068. [PMID: 35897642 PMCID: PMC9329908 DOI: 10.3390/ijms23158068] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 07/18/2022] [Accepted: 07/19/2022] [Indexed: 11/28/2022] Open
Abstract
Glaucomatous optic neuropathy is the leading cause of irreversible blindness in the world. The chronic disease is characterized by optic nerve degeneration and vision field loss. The reduction of intraocular pressure remains the only proven glaucoma treatment, but it does not prevent further neurodegeneration. There are three major classes of cells in the human optic nerve head (ONH): lamina cribrosa (LC) cells, glial cells, and scleral fibroblasts. These cells provide support for the LC which is essential to maintain healthy retinal ganglion cell (RGC) axons. All these cells demonstrate responses to glaucomatous conditions through extracellular matrix remodeling. Therefore, investigations into alternative therapies that alter the characteristic remodeling response of the ONH to enhance the survival of RGC axons are prevalent. Understanding major remodeling pathways in the ONH may be key to developing targeted therapies that reduce deleterious remodeling.
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Affiliation(s)
- Ryan G. Strickland
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA; (R.G.S.); (M.A.G.); (A.K.G.)
| | - Mary Anne Garner
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA; (R.G.S.); (M.A.G.); (A.K.G.)
| | - Alecia K. Gross
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA; (R.G.S.); (M.A.G.); (A.K.G.)
| | - Christopher A. Girkin
- Department of Ophthalmology and Vision Sciences, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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35
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Hydrogen sulfide supplement preserves mitochondrial function of retinal ganglion cell in a rat glaucoma model. Cell Tissue Res 2022; 389:171-185. [PMID: 35593936 DOI: 10.1007/s00441-022-03640-x] [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: 06/10/2021] [Accepted: 05/09/2022] [Indexed: 11/02/2022]
Abstract
Glaucoma is a neurodegenerative disease of visual system characterized by gradual loss of retinal ganglion cells (RGC). Since mitochondrial dysfunction of RGC is significantly involved in the pathological mechanisms of glaucoma, and hydrogen sulfide (H2S) takes part in the pathogeny of glaucoma and shows promising potential in restoring mitochondrial function in other neurons, the authors aimed to investigate the impact of H2S on mitochondrial function of RGC with a rat glaucoma model. An established chronic ocular hypertension (COH) rat model induced by injection of cross-linking hydrogel into anterior chamber was adopted, and a H2S donor, sodium hydrosulfide (NaHS), was selected to treat rats through intraperitoneal injection. After a period of 4 weeks, RGCs were isolated from the subjected rats with an immunopanning method and went through evaluations of mitochondrial membrane potential (MMP), mitochondrial permeability transition pore (MPTP) opening, intracellular Ca2 + level, reactive oxygen species (ROS) level, and cytosolic Cytochrome C distribution. The results showed that the mitochondrial function of RGC in experimental glaucoma was markedly improved by H2S supplement, being presented as stabilization of MMP, alleviation of MPTP opening, improvement of intracellular Ca2+ hemostasis, reduction of ROS accumulation, and inhibition of Cytochrome C release. Our study implicated that preservation of mitochondrial function by H2S probably plays a key role in protecting RGC in the context of glaucomatous neuropathy, and it is worth further deepgoing research to benefit the development of glaucoma treatment.
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36
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Carnazza KE, Komer LE, Xie YX, Pineda A, Briano JA, Gao V, Na Y, Ramlall T, Buchman VL, Eliezer D, Sharma M, Burré J. Synaptic vesicle binding of α-synuclein is modulated by β- and γ-synucleins. Cell Rep 2022; 39:110675. [PMID: 35417693 PMCID: PMC9116446 DOI: 10.1016/j.celrep.2022.110675] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Revised: 01/23/2022] [Accepted: 03/22/2022] [Indexed: 12/16/2022] Open
Abstract
α-synuclein, β-synuclein, and γ-synuclein are abundantly expressed proteins in the vertebrate nervous system. α-synuclein functions in neurotransmitter release by binding to and clustering synaptic vesicles and chaperoning SNARE-complex assembly. Pathologically, aggregates originating from soluble pools of α-synuclein are deposited into Lewy bodies in Parkinson's disease and related synucleinopathies. The functions of β-synuclein and γ-synuclein in presynaptic terminals remain poorly studied. Using in vitro liposome binding studies, circular dichroism spectroscopy, immunoprecipitation, and fluorescence resonance energy transfer (FRET) experiments on isolated synaptic vesicles in combination with subcellular fractionation of brains from synuclein mouse models, we show that β-synuclein and γ-synuclein have a reduced affinity toward synaptic vesicles compared with α-synuclein, and that heteromerization of β-synuclein or γ-synuclein with α-synuclein results in reduced synaptic vesicle binding of α-synuclein in a concentration-dependent manner. Our data suggest that β-synuclein and γ-synuclein are modulators of synaptic vesicle binding of α-synuclein and thereby reduce α-synuclein's physiological activity at the neuronal synapse.
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Affiliation(s)
- Kathryn E Carnazza
- Helen and Robert Appel Alzheimer's Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10021, USA
| | - Lauren E Komer
- Helen and Robert Appel Alzheimer's Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10021, USA
| | - Ying Xue Xie
- Helen and Robert Appel Alzheimer's Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10021, USA
| | - André Pineda
- Helen and Robert Appel Alzheimer's Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10021, USA
| | - Juan Antonio Briano
- Helen and Robert Appel Alzheimer's Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10021, USA
| | - Virginia Gao
- Helen and Robert Appel Alzheimer's Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10021, USA
| | - Yoonmi Na
- Helen and Robert Appel Alzheimer's Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10021, USA
| | - Trudy Ramlall
- Department of Biochemistry, Weill Cornell Medicine, New York, NY 10021, USA
| | - Vladimir L Buchman
- School of Biosciences, Cardiff University, Cardiff CF103AX, UK; Belgorod State National Research University, 85 Pobedy Street, Belgorod, Belgorod 308015, Russian Federation
| | - David Eliezer
- Department of Biochemistry, Weill Cornell Medicine, New York, NY 10021, USA
| | - Manu Sharma
- Helen and Robert Appel Alzheimer's Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10021, USA
| | - Jacqueline Burré
- Helen and Robert Appel Alzheimer's Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10021, USA.
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Wan T, Zhu W, Zhao Y, Zhang X, Ye R, Zuo M, Xu P, Huang Z, Zhang C, Xie Y, Liu X. Astrocytic phagocytosis contributes to demyelination after focal cortical ischemia in mice. Nat Commun 2022; 13:1134. [PMID: 35241660 PMCID: PMC8894352 DOI: 10.1038/s41467-022-28777-9] [Citation(s) in RCA: 76] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 02/11/2022] [Indexed: 01/24/2023] Open
Abstract
Ischemic stroke can cause secondary myelin damage in the white matter distal to the primary injury site. The contribution of astrocytes during secondary demyelination and the underlying mechanisms are unclear. Here, using a mouse of distal middle cerebral artery occlusion, we show that lipocalin-2 (LCN2), enriched in reactive astrocytes, expression increases in nonischemic areas of the corpus callosum upon injury. LCN2-expressing astrocytes acquire a phagocytic phenotype and are able to uptake myelin. Myelin removal is impaired in Lcn2−/− astrocytes. Inducing re-expression of truncated LCN2(Δ2–20) in astrocytes restores phagocytosis and leads to progressive demyelination in Lcn2−/− mice. Co-immunoprecipitation experiments show that LCN2 binds to low-density lipoprotein receptor-related protein 1 (LRP1) in astrocytes. Knockdown of Lrp1 reduces LCN2-induced myelin engulfment by astrocytes and reduces demyelination. Altogether, our findings suggest that LCN2/LRP1 regulates astrocyte-mediated myelin phagocytosis in a mouse model of ischemic stroke. Ischemic stroke can cause secondary demyelination. Whether phagocytic astrocytes can contribute to such demyelination is unclear. Here, the authors show that lipocalin-2 (LCN-2) expression increased in astrocytes upon injury. LCN-2 expressing astrocytes acquire a phagocytic phenotype and contribute to secondary demyelination in a mouse model of ischemic stroke.
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Affiliation(s)
- Ting Wan
- Department of Neurology, Affiliated Jinling Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, 210000, China
| | - Wusheng Zhu
- Department of Neurology, Affiliated Jinling Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, 210000, China
| | - Ying Zhao
- Department of Neurology, Affiliated Jinling Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, 210000, China
| | - Xiaohao Zhang
- Department of Neurology, Affiliated Jinling Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, 210000, China
| | - Ruidong Ye
- Department of Neurology, Affiliated Jinling Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, 210000, China
| | - Meng Zuo
- Department of Neurology, Southwest Hospital and the First Affiliated Hospital, Army Medical University, Chongqing, 400000, China
| | - Pengfei Xu
- Stroke Center & Department of Neurology, The Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230036, Anhui, China
| | - Zhenqian Huang
- Department of Neurology, Affiliated Jinling Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, 210000, China
| | - Chunni Zhang
- Department of Clinical Laboratory, Affiliated Jinling Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, 210000, China.
| | - Yi Xie
- Department of Neurology, Affiliated Jinling Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, 210000, China.
| | - Xinfeng Liu
- Department of Neurology, Affiliated Jinling Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, 210000, China. .,Stroke Center & Department of Neurology, The Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230036, Anhui, China.
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38
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Molecular regulation of neuroinflammation in glaucoma: Current knowledge and the ongoing search for new treatment targets. Prog Retin Eye Res 2022; 87:100998. [PMID: 34348167 PMCID: PMC8803988 DOI: 10.1016/j.preteyeres.2021.100998] [Citation(s) in RCA: 82] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 07/23/2021] [Accepted: 07/26/2021] [Indexed: 12/11/2022]
Abstract
Neuroinflammation relying on the inflammatory responses of glial cells has emerged as an impactful component of the multifactorial etiology of neurodegeneration in glaucoma. It has become increasingly evident that despite early adaptive and reparative features of glial responses, prolonged reactivity of the resident glia, along with the peripheral immune cells, create widespread toxicity to retinal ganglion cell (RGC) axons, somas, and synapses. As much as the synchronized responses of astrocytes and microglia to glaucoma-related stress or neuron injury, their bi-directional interactions are critical to build and amplify neuroinflammation and to dictate the neurodegenerative outcome. Although distinct molecular programs regulate somatic and axonal degeneration in glaucoma, inhibition of neurodegenerative inflammation can provide a broadly beneficial treatment strategy to rescue RGC integrity and function. Since inflammatory toxicity and mitochondrial dysfunction are converging etiological paths that can boost each other and feed into a vicious cycle, anti-inflammatory treatments may also offer a multi-target potential. This review presents an overview of the current knowledge on neuroinflammation in glaucoma with particular emphasis on the cell-intrinsic and cell-extrinsic factors involved in the reciprocal regulation of glial responses, the interdependence between inflammatory and mitochondrial routes of neurodegeneration, and the research aspects inspiring for prospective immunomodulatory treatments. With the advent of powerful technologies, ongoing research on molecular and functional characteristics of glial responses is expected to accumulate more comprehensive and complementary information and to rapidly move the field forward to safe and effective modulation of the glial pro-inflammatory activities, while restoring or augmenting the glial immune-regulatory and neurosupport functions.
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Pinto-Benito D, Paradela-Leal C, Ganchala D, de Castro-Molina P, Arevalo MA. IGF-1 regulates astrocytic phagocytosis and inflammation through the p110α isoform of PI3K in a sex-specific manner. Glia 2022; 70:1153-1169. [PMID: 35175663 PMCID: PMC9305764 DOI: 10.1002/glia.24163] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 01/18/2022] [Accepted: 02/10/2022] [Indexed: 12/12/2022]
Abstract
Insulin-like growth factor-I (IGF-I) signaling plays a key role in neuroinflammation. Here we show that IGF-1 also regulates phagocytosis of reactive astrocytes through p110α isoform of phosphatidylinositol 3-kinase (PI3K), differentially in both sexes. Systemic bacterial lipopolysaccharide (LPS)-treatment increased the expression of GFAP, a reactive astrocyte marker, in the cortex of mice in both sexes and was blocked by IGF-1 only in males. In primary astrocytes, LPS enhanced the mRNA expression of Toll-like receptors (TLR2,4) and proinflammatory factors: inducible nitric oxide synthase (iNOS), chemokine interferon-γ-inducible protein-10 (IP-10) and cytokines (IL-1β, IL-6, and IL-10) in male and female. Treatment with IGF-1 counteracted TLR4 but not TLR2, iNOS, and IP10 expression in both sexes and cytokines expression in males. Furthermore, reactive astrocyte phagocytosis was modulated by IGF-1 only in male astrocytes. IGF-1 was also able to increase AKT-phosphorylation only in male astrocytes. PI3K inhibitors, AG66, TGX-221, and CAL-101, with selectivity toward catalytic p110α, p110β, and p110δ isoforms respectively, reduced AKT-phosphorylation in males. All isoforms interact physically with IGF-1-receptor in both sexes. However, the expression of p110α is higher in males while the expression of IGF-1-receptor is similar in male and female. AG66 suppressed the IGF-1 effect on cytokine expression and counteracted the IGF-1-produced phagocytosis decrease in male reactive astrocytes. Results suggest that sex-differences in the effect of IGF-1 on the AKT-phosphorylation could be due to a lower expression of the p110α in female and that IGF-1-effects on the inflammatory response and phagocytosis of male reactive astrocytes are mediated by p110α/PI3K subunit.
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Affiliation(s)
- Daniel Pinto-Benito
- Consejo Superior de Investigaciones Científicas (CSIC), Instituto Cajal, Madrid, Spain.,Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable (CIBERFES), Instituto de Salud Carlos III, Madrid, Spain
| | - Carmen Paradela-Leal
- Consejo Superior de Investigaciones Científicas (CSIC), Instituto Cajal, Madrid, Spain
| | - Danny Ganchala
- Consejo Superior de Investigaciones Científicas (CSIC), Instituto Cajal, Madrid, Spain
| | | | - Maria-Angeles Arevalo
- Consejo Superior de Investigaciones Científicas (CSIC), Instituto Cajal, Madrid, Spain.,Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable (CIBERFES), Instituto de Salud Carlos III, Madrid, Spain
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40
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Konishi H, Koizumi S, Kiyama H. Phagocytic astrocytes: Emerging from the shadows of microglia. Glia 2022; 70:1009-1026. [PMID: 35142399 PMCID: PMC9305589 DOI: 10.1002/glia.24145] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 12/18/2021] [Accepted: 01/07/2022] [Indexed: 12/12/2022]
Abstract
Elimination of dead or live cells take place in both a healthy and diseased central nervous system (CNS). Dying or dead cells are quickly cleared by phagocytosis for the maintenance of a healthy CNS or for recovery after injury. Live cells or parts thereof, such as the synapses and myelin, are appropriately eliminated by phagocytosis to maintain or refine neural networks during development and adulthood. Microglia, the specific population of resident macrophages in the CNS, are classically considered as primary phagocytes; however, astrocytes have also been highlighted as phagocytes in the last decade. Phagocytic targets and receptors are reported to be mostly common between astrocytes and microglia, which raises the question of how astrocytic phagocytosis differs from microglial phagocytosis, and how these two phagocytic systems cooperate. In this review, we address the consequences of astrocytic phagocytosis, particularly focusing on these elusive points.
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Affiliation(s)
- Hiroyuki Konishi
- Department of Functional Anatomy and Neuroscience, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Schuichi Koizumi
- Department of Neuropharmacology, University of Yamanashi, Yamanashi, Japan.,GLIA Center, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Hiroshi Kiyama
- Department of Functional Anatomy and Neuroscience, Nagoya University Graduate School of Medicine, Nagoya, Japan
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41
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Yamashita H, Komine O, Fujimori-Tonou N, Yamanaka K. Comprehensive expression analysis with cell-type-specific transcriptome in ALS-linked mutant SOD1 mice: Revisiting the active role of glial cells in disease. Front Cell Neurosci 2022; 16:1045647. [PMID: 36687517 PMCID: PMC9846815 DOI: 10.3389/fncel.2022.1045647] [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: 09/15/2022] [Accepted: 12/05/2022] [Indexed: 01/06/2023] Open
Abstract
Non-cell autonomous mechanisms are involved in the pathogenesis of amyotrophic lateral sclerosis (ALS), an adult neurodegenerative disease characterized by selective motor neuron loss. While the emerging role of glial cells in ALS has been noted, the detailed cell-type-specific role of glial cells has not been clarified. Here, we examined mRNA expression changes using microarrays of the spinal cords of three distinct lines of mutant superoxide dismutase (SOD) 1 transgenic mice, an established ALS model. Our analysis used a transcriptome database of component cell types in the central nervous system (CNS), as well as SOD1 G93A cell-type transcriptomes. More than half of the differentially expressed genes (DEGs) were highly expressed in microglia, and enrichment analysis of DEGs revealed that immunological reactions were profoundly involved and some transcription factors were upregulated. Our analysis focused on DEGs that are highly expressed in each cell type, as well as chemokines, caspases, and heat shock proteins. Disease-associated microglial genes were upregulated, while homeostatic microglial genes were not, and galectin-3 (Mac2), a known activated microglial marker, was predicted to be ectopically expressed in astrocytes in mutant SOD1 mice. In mutant SOD1 mice, we developed a prediction model for the pathophysiology of different cell types related to TREM2, apolipoprotein E, and lipoproteins. Our analysis offers a viable resource to understand not only the molecular pathologies of each CNS constituent cell type, but also the cellular crosstalk between different cell types under both physiological and pathological conditions in model mice for various neurodegenerative diseases.
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Affiliation(s)
- Hirofumi Yamashita
- Department of Neurology, Japanese Red Cross Wakayama Medical Center, Wakayama, Japan.,Department of Neurology, Graduate School of Medicine, Kyoto University, Kyoto, Japan.,Department of Neuroscience and Pathobiology, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan
| | - Okiru Komine
- Department of Neuroscience and Pathobiology, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan
| | - Noriko Fujimori-Tonou
- Support Unit for Bio-Material Analysis, RRD, RIKEN Center for Brain Science, Wako, Japan
| | - Koji Yamanaka
- Department of Neuroscience and Pathobiology, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan.,Department of Neuroscience and Pathobiology, Nagoya University Graduate School of Medicine, Nagoya University, Nagoya, Japan.,Institute for Glyco-Core Research (iGCORE), Nagoya University, Nagoya, Japan
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42
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Lo HP, Lim YW, Xiong Z, Martel N, Ferguson C, Ariotti N, Giacomotto J, Rae J, Floetenmeyer M, Moradi SV, Gao Y, Tillu VA, Xia D, Wang H, Rahnama S, Nixon SJ, Bastiani M, Day RD, Smith KA, Palpant NJ, Johnston WA, Alexandrov K, Collins BM, Hall TE, Parton RG. Cavin4 interacts with Bin1 to promote T-tubule formation and stability in developing skeletal muscle. J Cell Biol 2021; 220:e201905065. [PMID: 34633413 PMCID: PMC8513623 DOI: 10.1083/jcb.201905065] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 06/02/2021] [Accepted: 09/20/2021] [Indexed: 11/22/2022] Open
Abstract
The cavin proteins are essential for caveola biogenesis and function. Here, we identify a role for the muscle-specific component, Cavin4, in skeletal muscle T-tubule development by analyzing two vertebrate systems, mouse and zebrafish. In both models, Cavin4 localized to T-tubules, and loss of Cavin4 resulted in aberrant T-tubule maturation. In zebrafish, which possess duplicated cavin4 paralogs, Cavin4b was shown to directly interact with the T-tubule-associated BAR domain protein Bin1. Loss of both Cavin4a and Cavin4b caused aberrant accumulation of interconnected caveolae within the T-tubules, a fragmented T-tubule network enriched in Caveolin-3, and an impaired Ca2+ response upon mechanical stimulation. We propose a role for Cavin4 in remodeling the T-tubule membrane early in development by recycling caveolar components from the T-tubule to the sarcolemma. This generates a stable T-tubule domain lacking caveolae that is essential for T-tubule function.
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Affiliation(s)
- Harriet P. Lo
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Ye-Wheen Lim
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Zherui Xiong
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Nick Martel
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Charles Ferguson
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Nicholas Ariotti
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Jean Giacomotto
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
- Queensland Centre for Mental Health Research, West Moreton Hospital and Health Service and University of Queensland, Brisbane, Queensland, Australia
| | - James Rae
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Matthias Floetenmeyer
- Centre for Microscopy and Microanalysis, The University of Queensland, Brisbane, Queensland, Australia
| | - Shayli Varasteh Moradi
- CSIRO–Queensland University of Technology Synthetic Biology Alliance, ARC Centre of Excellence in Synthetic Biology, Centre for Agriculture and the Bioeconomy, School of Biology and Environmental Science, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Ya Gao
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Vikas A. Tillu
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Di Xia
- Genome Innovation Hub, The University of Queensland, Brisbane, Queensland, Australia
| | - Huang Wang
- Translational Research Institute, Mater Research Institute, The University of Queensland, Brisbane, Queensland, Australia
| | - Samira Rahnama
- CSIRO–Queensland University of Technology Synthetic Biology Alliance, ARC Centre of Excellence in Synthetic Biology, Centre for Agriculture and the Bioeconomy, School of Biology and Environmental Science, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Susan J. Nixon
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Michele Bastiani
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Ryan D. Day
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Kelly A. Smith
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Nathan J. Palpant
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Wayne A. Johnston
- CSIRO–Queensland University of Technology Synthetic Biology Alliance, ARC Centre of Excellence in Synthetic Biology, Centre for Agriculture and the Bioeconomy, School of Biology and Environmental Science, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Kirill Alexandrov
- CSIRO–Queensland University of Technology Synthetic Biology Alliance, ARC Centre of Excellence in Synthetic Biology, Centre for Agriculture and the Bioeconomy, School of Biology and Environmental Science, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Brett M. Collins
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Thomas E. Hall
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Robert G. Parton
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
- Centre for Microscopy and Microanalysis, The University of Queensland, Brisbane, Queensland, Australia
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43
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Lamboley CR, Pearce L, Seng C, Meizoso-Huesca A, Singh DP, Frankish BP, Kaura V, Lo HP, Ferguson C, Allen PD, Hopkins PM, Parton RG, Murphy RM, van der Poel C, Barclay CJ, Launikonis BS. Ryanodine receptor leak triggers fiber Ca 2+ redistribution to preserve force and elevate basal metabolism in skeletal muscle. SCIENCE ADVANCES 2021; 7:eabi7166. [PMID: 34705503 PMCID: PMC8550231 DOI: 10.1126/sciadv.abi7166] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Muscle contraction depends on tightly regulated Ca2+ release. Aberrant Ca2+ leak through ryanodine receptor 1 (RyR1) on the sarcoplasmic reticulum (SR) membrane can lead to heatstroke and malignant hyperthermia (MH) susceptibility, as well as severe myopathy. However, the mechanism by which Ca2+ leak drives these pathologies is unknown. Here, we investigate the effects of four mouse genotypes with increasingly severe RyR1 leak in skeletal muscle fibers. We find that RyR1 Ca2+ leak initiates a cascade of events that cause precise redistribution of Ca2+ among the SR, cytoplasm, and mitochondria through altering the Ca2+ permeability of the transverse tubular system membrane. This redistribution of Ca2+ allows mice with moderate RyR1 leak to maintain normal function; however, severe RyR1 leak with RYR1 mutations reduces the capacity to generate force. Our results reveal the mechanism underlying force preservation, increased ATP metabolism, and susceptibility to MH in individuals with gain-of-function RYR1 mutations.
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Affiliation(s)
- Cedric R. Lamboley
- School of Biomedical Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Luke Pearce
- School of Biomedical Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Crystal Seng
- School of Biomedical Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Aldo Meizoso-Huesca
- School of Biomedical Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Daniel P. Singh
- School of Biomedical Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Barnaby P. Frankish
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC 3086, Australia
| | - Vikas Kaura
- Leeds Institute of Medical Research, University of Leeds, Leeds, UK
| | - Harriet P. Lo
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
| | - Charles Ferguson
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
| | - Paul D. Allen
- Leeds Institute of Medical Research, University of Leeds, Leeds, UK
| | | | - Robert G. Parton
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
- Centre for Microscopy and Microanalysis, The University of Queensland, Brisbane, QLD, Australia
| | - Robyn M. Murphy
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC 3086, Australia
- Department of Physiology Anatomy and Microbiology, La Trobe University, Melbourne, VIC 3086, Australia
| | - Chris van der Poel
- Department of Physiology Anatomy and Microbiology, La Trobe University, Melbourne, VIC 3086, Australia
| | - Christopher J. Barclay
- School of Biomedical Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Bradley S. Launikonis
- School of Biomedical Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
- Corresponding author.
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Basilico B, Ferrucci L, Ratano P, Golia MT, Grimaldi A, Rosito M, Ferretti V, Reverte I, Sanchini C, Marrone MC, Giubettini M, De Turris V, Salerno D, Garofalo S, St-Pierre MK, Carrier M, Renzi M, Pagani F, Modi B, Raspa M, Scavizzi F, Gross CT, Marinelli S, Tremblay MÈ, Caprioli D, Maggi L, Limatola C, Di Angelantonio S, Ragozzino D. Microglia control glutamatergic synapses in the adult mouse hippocampus. Glia 2021; 70:173-195. [PMID: 34661306 PMCID: PMC9297980 DOI: 10.1002/glia.24101] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Revised: 09/20/2021] [Accepted: 09/27/2021] [Indexed: 12/26/2022]
Abstract
Microglia cells are active players in regulating synaptic development and plasticity in the brain. However, how they influence the normal functioning of synapses is largely unknown. In this study, we characterized the effects of pharmacological microglia depletion, achieved by administration of PLX5622, on hippocampal CA3‐CA1 synapses of adult wild type mice. Following microglial depletion, we observed a reduction of spontaneous and evoked glutamatergic activity associated with a decrease of dendritic spine density. We also observed the appearance of immature synaptic features and higher levels of plasticity. Microglia depleted mice showed a deficit in the acquisition of the Novel Object Recognition task. These events were accompanied by hippocampal astrogliosis, although in the absence ofneuroinflammatory condition. PLX‐induced synaptic changes were absent in Cx3cr1−/− mice, highlighting the role of CX3CL1/CX3CR1 axis in microglia control of synaptic functioning. Remarkably, microglia repopulation after PLX5622 withdrawal was associated with the recovery of hippocampal synapses and learning functions. Altogether, these data demonstrate that microglia contribute to normal synaptic functioning in the adult brain and that their removal induces reversible changes in organization and activity of glutamatergic synapses.
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Affiliation(s)
- Bernadette Basilico
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy
| | - Laura Ferrucci
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy
| | - Patrizia Ratano
- Neurophysiology and Neuropharmacology Inflammaging Unit, IRCCS Neuromed, Mediterranean Neurological Institute, Pozzilli, IS, Italy
| | - Maria T Golia
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy
| | - Alfonso Grimaldi
- Center for Life Nano- and Neuro-science, Istituto Italiano di Tecnologia, Rome, Italy
| | - Maria Rosito
- Center for Life Nano- and Neuro-science, Istituto Italiano di Tecnologia, Rome, Italy
| | - Valentina Ferretti
- Dipartimento di Biologia e Biotecnologie "Charles Darwin", Sapienza University of Rome, Rome, Italy
| | - Ingrid Reverte
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy.,Santa Lucia Foundation (IRCCS Fondazione Santa Lucia), Rome, Italy
| | - Caterina Sanchini
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy.,Center for Life Nano- and Neuro-science, Istituto Italiano di Tecnologia, Rome, Italy
| | - Maria C Marrone
- European Brain Research Institute (EBRI) 'Rita Levi-Montalcini', Rome, Italy
| | - Maria Giubettini
- Center for Life Nano- and Neuro-science, Istituto Italiano di Tecnologia, Rome, Italy.,CrestOptics S.p.A, Rome, Italy
| | - Valeria De Turris
- Center for Life Nano- and Neuro-science, Istituto Italiano di Tecnologia, Rome, Italy
| | - Debora Salerno
- Center for Life Nano- and Neuro-science, Istituto Italiano di Tecnologia, Rome, Italy
| | - Stefano Garofalo
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy
| | - Marie-Kim St-Pierre
- Centre de Recherche du CHU de Québec, Axe Neurosciences Québec, Quebec City, Canada.,Département de Médecine Moléculaire, Université Laval Québec, Quebec City, Canada
| | - Micael Carrier
- Centre de Recherche du CHU de Québec, Axe Neurosciences Québec, Quebec City, Canada.,Département de Médecine Moléculaire, Université Laval Québec, Quebec City, Canada
| | - Massimiliano Renzi
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy
| | - Francesca Pagani
- Center for Life Nano- and Neuro-science, Istituto Italiano di Tecnologia, Rome, Italy
| | - Brijesh Modi
- European Brain Research Institute (EBRI) 'Rita Levi-Montalcini', Rome, Italy
| | - Marcello Raspa
- National Research Council, Institute of Biochemistry and Cell Biology (CNR-IBBC/EMMA/Infrafrontier/IMPC), International Campus "A. Buzzati-Traverso", Monterotondo (Rome), Italy
| | - Ferdinando Scavizzi
- National Research Council, Institute of Biochemistry and Cell Biology (CNR-IBBC/EMMA/Infrafrontier/IMPC), International Campus "A. Buzzati-Traverso", Monterotondo (Rome), Italy
| | - Cornelius T Gross
- Epigenetics and Neurobiology Unit, European Molecular Biology Laboratory (EMBL), Monterotondo, Italy
| | - Silvia Marinelli
- European Brain Research Institute (EBRI) 'Rita Levi-Montalcini', Rome, Italy
| | - Marie-Ève Tremblay
- Centre de Recherche du CHU de Québec, Axe Neurosciences Québec, Quebec City, Canada.,Département de Médecine Moléculaire, Université Laval Québec, Quebec City, Canada.,Division of Medical Sciences, University of Victoria, Victoria, Canada
| | - Daniele Caprioli
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy.,Santa Lucia Foundation (IRCCS Fondazione Santa Lucia), Rome, Italy
| | - Laura Maggi
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy
| | - Cristina Limatola
- Neurophysiology and Neuropharmacology Inflammaging Unit, IRCCS Neuromed, Mediterranean Neurological Institute, Pozzilli, IS, Italy.,Department of Physiology and Pharmacology, Sapienza University, Laboratory affiliated to Istituto Pasteur Italia, Rome, Italy
| | - Silvia Di Angelantonio
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy.,Center for Life Nano- and Neuro-science, Istituto Italiano di Tecnologia, Rome, Italy
| | - Davide Ragozzino
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy.,Santa Lucia Foundation (IRCCS Fondazione Santa Lucia), Rome, Italy
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The Multiple Roles of Trogocytosis in Immunity, the Nervous System, and Development. BIOMED RESEARCH INTERNATIONAL 2021; 2021:1601565. [PMID: 34604381 PMCID: PMC8483919 DOI: 10.1155/2021/1601565] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Revised: 09/02/2021] [Accepted: 09/08/2021] [Indexed: 12/24/2022]
Abstract
Trogocytosis is a general biological process that involves one cell physically taking small parts of the membrane and other components from another cell. In trogocytosis, one cell seems to take little “bites” from another cell resulting in multiple outcomes from these cell-cell interactions. Trogocytosis was first described in protozoan parasites, which by taking pieces of host cells, kill them and cause tissue damage. Now, it is known that this process is also performed by cells of the immune system with important consequences such as cell communication and activation, elimination of microbial pathogens, and even control of cancer cells. More recently, trogocytosis has also been reported to occur in cells of the central nervous system and in various cells during development. Some of the molecules involved in phagocytosis also participate in trogocytosis. However, the molecular mechanisms that regulate trogocytosis are still a mystery. Elucidating these mechanisms is becoming a research area of much interest. For example, why neutrophils can engage trogocytosis to kill Trichomonas vaginalis parasites, but neutrophils use phagocytosis to eliminate already death parasites? Thus, trogocytosis is a significant process in normal physiology that multiple cells from different organisms use in various scenarios of health and disease. In this review, we present the basic principles known on the process of trogocytosis and discuss the importance in this process to host-pathogen interactions and to normal functions in the immune and nervous systems.
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46
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Boghdadi AG, Teo L, Bourne JA. The Neuroprotective Role of Reactive Astrocytes after Central Nervous System Injury. J Neurotrauma 2021; 37:681-691. [PMID: 32031052 DOI: 10.1089/neu.2019.6938] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Reactive astrocytes have traditionally been viewed as a significant contributor to secondary neuronal damage and repair inhibition after central nervous system (CNS) injury attributed, in large part, to their roles in glial scarring. However, more recent transcriptional evidence has uncovered the vast diversity in reactive astrocyte identity and functions that comprises both neuroprotective and -toxic characteristics. Additionally, the capacity of reactive astrocytes to shift between these activation states demonstrates a high level of environment-dependent plasticity that drives the interplay between neuroprotection and -toxicity after CNS injury. These recent findings have spawned a new field of research that seeks to identify and categorize the function of these discrete subpopulations in the context of neurotrauma, as well as identify their regulators. Therefore, this review will discuss the major and most recent advances in this field of research, with a primary emphasis on neuroprotection. This review will also discuss the major pitfalls present in the field, with a particular focus on model species and their impact on the development of novel therapies.
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Affiliation(s)
| | - Leon Teo
- Australian Regenerative Medicine Institute, Monash University, Clayton, Victoria, Australia
| | - James Andrew Bourne
- Australian Regenerative Medicine Institute, Monash University, Clayton, Victoria, Australia
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47
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Van Broeckhoven J, Sommer D, Dooley D, Hendrix S, Franssen AJPM. Macrophage phagocytosis after spinal cord injury: when friends become foes. Brain 2021; 144:2933-2945. [PMID: 34244729 DOI: 10.1093/brain/awab250] [Citation(s) in RCA: 83] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 06/12/2021] [Accepted: 06/20/2021] [Indexed: 11/14/2022] Open
Abstract
After spinal cord injury (SCI), macrophages can exert either beneficial or detrimental effects depending on their phenotype. Aside from their critical role in inflammatory responses, macrophages are also specialized in the recognition, engulfment, and degradation of pathogens, apoptotic cells, and tissue debris. They promote remyelination and axonal regeneration by removing inhibitory myelin components and cellular debris. However, excessive intracellular presence of lipids and dysregulated intracellular lipid homeostasis result in the formation of foamy macrophages. These develop a pro-inflammatory phenotype that may contribute to further neurological decline. Additionally, myelin-activated macrophages play a crucial role in axonal dieback and retraction. Here, we review the opposing functional consequences of phagocytosis by macrophages in SCI, including remyelination and regeneration versus demyelination, degeneration, and axonal dieback. Furthermore, we discuss how targeting the phagocytic ability of macrophages may have therapeutic potential for the treatment of SCI.
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Affiliation(s)
- Jana Van Broeckhoven
- Department of Immunology and Infection, Biomedical Research Institute, Hasselt University, Diepenbeek, Belgium
| | - Daniela Sommer
- Department of Immunology and Infection, Biomedical Research Institute, Hasselt University, Diepenbeek, Belgium
| | - Dearbhaile Dooley
- School of Medicine, Health Sciences Centre, University College Dublin, Belfield Dublin 4, Ireland.,UCD Conway Institute of Biomolecular & Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
| | - Sven Hendrix
- Department of Immunology and Infection, Biomedical Research Institute, Hasselt University, Diepenbeek, Belgium.,Medical School Hamburg, Hamburg, Germany
| | - Aimée J P M Franssen
- Department of Immunology and Infection, Biomedical Research Institute, Hasselt University, Diepenbeek, Belgium
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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: 38] [Impact Index Per Article: 9.5] [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.
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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:
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Ribeiro TN, Delgado-García LM, Porcionatto MA. Notch1 and Galectin-3 Modulate Cortical Reactive Astrocyte Response After Brain Injury. Front Cell Dev Biol 2021; 9:649854. [PMID: 34222228 PMCID: PMC8244823 DOI: 10.3389/fcell.2021.649854] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 05/04/2021] [Indexed: 12/23/2022] Open
Abstract
After a brain lesion, highly specialized cortical astrocytes react, supporting the closure or replacement of the damaged tissue, but fail to regulate neural plasticity. Growing evidence indicates that repair response leads astrocytes to reprogram, acquiring a partially restricted regenerative phenotype in vivo and neural stem cells (NSC) hallmarks in vitro. However, the molecular factors involved in astrocyte reactivity, the reparative response, and their relation to adult neurogenesis are poorly understood and remain an area of intense investigation in regenerative medicine. In this context, we addressed the role of Notch1 signaling and the effect of Galectin-3 (Gal3) as underlying molecular candidates involved in cortical astrocyte response to injury. Notch signaling is part of a specific neurogenic microenvironment that maintains NSC and neural progenitors, and Gal3 has a preferential spatial distribution across the cortex and has a central role in the proliferative capacity of reactive astrocytes. We report that in vitro scratch-reactivated cortical astrocytes from C57Bl/6J neonatal mice present nuclear Notch1 intracellular domain (NICD1), indicating Notch1 activation. Colocalization analysis revealed a subpopulation of reactive astrocytes at the lesion border with colocalized NICD1/Jagged1 complexes compared with astrocytes located far from the border. Moreover, we found that Gal3 increased intracellularly, in contrast to its extracellular localization in non-reactive astrocytes, and NICD1/Gal3 pattern distribution shifted from diffuse to vesicular upon astrocyte reactivation. In vitro, Gal3–/– reactive astrocytes showed abolished Notch1 signaling at the lesion core. Notch1 receptor, its ligands (Jagged1 and Delta-like1), and Hes5 target gene were upregulated in C57Bl/6J reactive astrocytes, but not in Gal3–/– reactive astrocytes. Finally, we report that Gal3–/– mice submitted to a traumatic brain injury model in the somatosensory cortex presented a disrupted response characterized by the reduced number of GFAP reactive astrocytes, with smaller cell body perimeter and decreased NICD1 presence at the lesion core. These results suggest that Gal3 might be essential to the proper activation of Notch signaling, facilitating the cleavage of Notch1 and nuclear translocation of NICD1 into the nucleus of reactive cortical astrocytes. Additionally, we hypothesize that reactive astrocyte response could be dependent on Notch1/Jagged1-Hes5 signaling activation following brain injury.
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Affiliation(s)
- Tais Novaki Ribeiro
- Laboratory of Molecular Neurobiology, Department of Biochemistry, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Lina Maria Delgado-García
- Laboratory of Molecular Neurobiology, Department of Biochemistry, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Marimelia A Porcionatto
- Laboratory of Molecular Neurobiology, Department of Biochemistry, Universidade Federal de São Paulo, São Paulo, Brazil
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Zhao X, Sun R, Luo X, Wang F, Sun X. The Interaction Between Microglia and Macroglia in Glaucoma. Front Neurosci 2021; 15:610788. [PMID: 34121982 PMCID: PMC8193936 DOI: 10.3389/fnins.2021.610788] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Accepted: 04/22/2021] [Indexed: 01/11/2023] Open
Abstract
Glaucoma, a neurodegenerative disease that leads to irreversible vision loss, is characterized by progressive loss of retinal ganglion cells (RGCs) and optic axons. To date, elevated intraocular pressure (IOP) has been recognized as the main phenotypic factor associated with glaucoma. However, some patients with normal IOP also have glaucomatous visual impairment and RGC loss. Unfortunately, the underlying mechanisms behind such cases remain unclear. Recent studies have suggested that retinal glia play significant roles in the initiation and progression of glaucoma. Multiple types of glial cells are activated in glaucoma. Microglia, for example, act as critical mediators that orchestrate the progression of neuroinflammation through pro-inflammatory cytokines. In contrast, macroglia (astrocytes and Müller cells) participate in retinal inflammatory responses as modulators and contribute to neuroprotection through the secretion of neurotrophic factors. Notably, research results have indicated that intricate interactions between microglia and macroglia might provide potential therapeutic targets for the prevention and treatment of glaucoma. In this review, we examine the specific roles of microglia and macroglia in open-angle glaucoma, including glaucoma in animal models, and analyze the interaction between these two cell types. In addition, we discuss potential treatment options based on the relationship between glial cells and neurons.
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Affiliation(s)
- Xiaohuan Zhao
- Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai General Hospital, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai, China
| | - Rou Sun
- Department of Ophthalmology, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xueting Luo
- Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai General Hospital, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai, China
| | - Feng Wang
- Department of Immunology and Microbiology, Shanghai General Hospital, The Center for Microbiota and Immunological Diseases, Shanghai Institute of Immunology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiaodong Sun
- Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai General Hospital, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai, China
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