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Rorex C, Cardona SM, Church KA, Rodriguez D, Vanegas D, Saldivar R, Faz B, Cardona AE. Astrogliosis in the GFAP-Cre ERT2:Rosa26 iDTR Mouse Model Does Not Exacerbate Retinal Microglia Activation or Müller Cell Gliosis under Hypoxic Conditions. Biomolecules 2024; 14:567. [PMID: 38785974 PMCID: PMC11117533 DOI: 10.3390/biom14050567] [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: 03/29/2024] [Revised: 04/26/2024] [Accepted: 05/08/2024] [Indexed: 05/25/2024] Open
Abstract
Diabetic retinopathy (DR) affects over 140 million people globally. The mechanisms that lead to blindness are still enigmatic but there is evidence that sustained inflammation and hypoxia contribute to vascular damage. Despite efforts to understand the role of inflammation and microglia in DR's pathology, the contribution of astrocytes to hypoxic responses is less clear. To investigate the role of astrocytes in hypoxia-induced retinopathy, we utilized a 7-day systemic hypoxia model using the GFAP-CreERT2:Rosa26iDTR transgenic mouse line. This allows for the induction of inflammatory reactive astrogliosis following tamoxifen and diphtheria toxin administration. We hypothesize that DTx-induced astrogliosis is neuroprotective during hypoxia-induced retinopathy. Glial, neuronal, and vascular responses were quantified using immunostaining, with antibodies against GFAP, vimentin, IBA-1, NeuN, fibrinogen, and CD31. Cytokine responses were measured in both the brain and serum. We report that while both DTx and hypoxia induced a phenotype of reduced microglia morphological activation, DTx, but not hypoxia, induced an increase in the Müller glia marker vimentin. We did not observe that the combination of DTx and hypoxic treatments exacerbated the signs of reactive glial cells, nor did we observe a significant change in the expression immunomodulatory mediators IL-1β, IL2, IL-4, IL-5, IL-6, IL-10, IL-18, CCL17, TGF-β1, GM-CSF, TNF-α, and IFN-γ. Overall, our results suggest that, in this hypoxia model, reactive astrogliosis does not alter the inflammatory responses or cause vascular damage in the retina.
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Affiliation(s)
- Colin Rorex
- Molecular Microbiology and Immunology, College of Sciences, The University of Texas at San Antonio, San Antonio, TX 78249, USA; (C.R.)
| | - Sandra M. Cardona
- Molecular Microbiology and Immunology, College of Sciences, The University of Texas at San Antonio, San Antonio, TX 78249, USA; (C.R.)
| | - Kaira A. Church
- Molecular Microbiology and Immunology, College of Sciences, The University of Texas at San Antonio, San Antonio, TX 78249, USA; (C.R.)
| | - Derek Rodriguez
- Molecular Microbiology and Immunology, College of Sciences, The University of Texas at San Antonio, San Antonio, TX 78249, USA; (C.R.)
- Integrative Biology, The University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - Difernando Vanegas
- Molecular Microbiology and Immunology, College of Sciences, The University of Texas at San Antonio, San Antonio, TX 78249, USA; (C.R.)
| | - Reina Saldivar
- Molecular Microbiology and Immunology, College of Sciences, The University of Texas at San Antonio, San Antonio, TX 78249, USA; (C.R.)
| | - Brianna Faz
- Integrative Biology, The University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - Astrid E. Cardona
- Molecular Microbiology and Immunology, College of Sciences, The University of Texas at San Antonio, San Antonio, TX 78249, USA; (C.R.)
- South Texas Center for Emerging Infectious Diseases, The University of Texas at San Antonio, San Antonio, TX 78249, USA
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Shigetomi E, Sakai K, Koizumi S. Extracellular ATP/adenosine dynamics in the brain and its role in health and disease. Front Cell Dev Biol 2024; 11:1343653. [PMID: 38304611 PMCID: PMC10830686 DOI: 10.3389/fcell.2023.1343653] [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: 11/24/2023] [Accepted: 12/31/2023] [Indexed: 02/03/2024] Open
Abstract
Extracellular ATP and adenosine are neuromodulators that regulate numerous neuronal functions in the brain. Neuronal activity and brain insults such as ischemic and traumatic injury upregulate these neuromodulators, which exert their effects by activating purinergic receptors. In addition, extracellular ATP/adenosine signaling plays a pivotal role in the pathogenesis of neurological diseases. Virtually every cell type in the brain contributes to the elevation of ATP/adenosine, and various mechanisms underlying this increase have been proposed. Extracellular adenosine is thought to be mainly produced via the degradation of extracellular ATP. However, adenosine is also released from neurons and glia in the brain. Therefore, the regulation of extracellular ATP/adenosine in physiological and pathophysiological conditions is likely far more complex than previously thought. To elucidate the complex mechanisms that regulate extracellular ATP/adenosine levels, accurate methods of assessing their spatiotemporal dynamics are needed. Several novel techniques for acquiring spatiotemporal information on extracellular ATP/adenosine, including fluorescent sensors, have been developed and have started to reveal the mechanisms underlying the release, uptake and degradation of ATP/adenosine. Here, we review methods for analyzing extracellular ATP/adenosine dynamics as well as the current state of knowledge on the spatiotemporal dynamics of ATP/adenosine in the brain. We focus on the mechanisms used by neurons and glia to cooperatively produce the activity-dependent increase in ATP/adenosine and its physiological and pathophysiological significance in the brain.
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Affiliation(s)
- Eiji Shigetomi
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Chuo, Japan
- Yamanashi GLIA Center, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Chuo, Japan
| | - Kent Sakai
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Chuo, Japan
- Yamanashi GLIA Center, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Chuo, Japan
| | - Schuichi Koizumi
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Chuo, Japan
- Yamanashi GLIA Center, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Chuo, Japan
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3
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Quarta A, Gironi M, Ruggeri ML, Aharrh-Gnama A, Porreca A, D'Aloisio R, Toto L, Di Nicola M, Mastropasqua R. Baseline imaging characteristics and early structural changes in macula on rhegmatogenous retinal detachment. Sci Rep 2024; 14:1370. [PMID: 38228760 DOI: 10.1038/s41598-024-51183-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 01/01/2024] [Indexed: 01/18/2024] Open
Abstract
Animal models have demonstrated that structural changes affect the macula during peripheral rhegmatogenous retinal detachment. This study aimed to assess photoreceptors, retinal and choriocapillaris perfusion in non-macula involving rhegmatogenous retinal detachment by analyzing en-face images from structural OCTA segmented at the ellipsoid zone (EZ) level, calculating (1) "normalized" reflectivity as a surrogate biomarker of photoreceptor damage (2) perfusion density (PD), vessel length density (VLD) and vessel diameter index (VDI) of superficial capillary plexus (SCP) and deep capillary plexus (DCP) (3) perfusion density of choriocapillaris (PDCC). Twenty-one eyes affected by macula-on rhegmatogenous retinal detachment (RRD) were enrolled at the University "G. d'Annunzio", Chieti-Pescara. The fellow unaffected eye was used as control. The mean age at the onset of RRD was 60.09 ± 10.22 (range 34-83). Compared with fellow eyes, we found lower EZ "normalized" reflectivity in macula-on (0.42 ± 0.15 in fellow eyes and 0.31 ± 0.09 in macula on p = 0.004). The affected eye was also characterized by impaired perfusion in SCP (17.26 ± 3.34% in macula on and 20.56 ± 3.62% in the fellow eye p = 0.004) and CC (50.21 ± 6.20% in macula on the eye and 57.43 ± 6.20% in the fellow eye p = 0.004). Macula-on rhegmatogenous retinal detachment has subclinical changes in photoreceptors, SCP, and CC. Future longitudinal studies should evaluate if early changes could impact post-operative macular function.
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Affiliation(s)
- Alberto Quarta
- Department of Sciences, Ophthalmology Clinic, National Center of High Technology in Ophthalmology, Gabriele D'Annunzio University, Via dei Vestini, 66100, Chieti, Italy.
| | - Matteo Gironi
- Department of Sciences, Ophthalmology Clinic, National Center of High Technology in Ophthalmology, Gabriele D'Annunzio University, Via dei Vestini, 66100, Chieti, Italy
| | - Maria Ludovica Ruggeri
- Department of Sciences, Ophthalmology Clinic, National Center of High Technology in Ophthalmology, Gabriele D'Annunzio University, Via dei Vestini, 66100, Chieti, Italy
| | - Agbeanda Aharrh-Gnama
- Department of Sciences, Ophthalmology Clinic, National Center of High Technology in Ophthalmology, Gabriele D'Annunzio University, Via dei Vestini, 66100, Chieti, Italy
| | - Annamaria Porreca
- Department of Medical Oral Science and Biotechnology, G. d'Annunzio University of Chieti-Pescara Chieti, Via dei Vestini 31, Chieti, Italy
| | - Rossella D'Aloisio
- Department of Sciences, Ophthalmology Clinic, National Center of High Technology in Ophthalmology, Gabriele D'Annunzio University, Via dei Vestini, 66100, Chieti, Italy
| | - Lisa Toto
- Department of Sciences, Ophthalmology Clinic, National Center of High Technology in Ophthalmology, Gabriele D'Annunzio University, Via dei Vestini, 66100, Chieti, Italy
| | - Marta Di Nicola
- Department of Medical Oral Science and Biotechnology, G. d'Annunzio University of Chieti-Pescara Chieti, Via dei Vestini 31, Chieti, Italy
| | - Rodolfo Mastropasqua
- Department of Sciences, Ophthalmology Clinic, National Center of High Technology in Ophthalmology, Gabriele D'Annunzio University, Via dei Vestini, 66100, Chieti, Italy
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Kreitzer MA, Vredeveld M, Tinner K, Powell AM, Schantz AW, Leininger R, Merillat R, Gongwer MW, Tchernookova BK, Malchow RP. ATP-mediated increase in H + efflux from retinal Müller cells of the axolotl. J Neurophysiol 2024; 131:124-136. [PMID: 38116604 DOI: 10.1152/jn.00321.2023] [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: 08/25/2023] [Revised: 11/17/2023] [Accepted: 12/13/2023] [Indexed: 12/21/2023] Open
Abstract
Previous work has shown that activation of tiger salamander retinal radial glial cells by extracellular ATP induces a pronounced extracellular acidification, which has been proposed to be a potent modulator of neurotransmitter release. This study demonstrates that low micromolar concentrations of extracellular ATP similarly induce significant H+ effluxes from Müller cells isolated from the axolotl retina. Müller cells were enzymatically isolated from axolotl retina and H+ fluxes were measured from individual cells using self-referencing H+-selective microelectrodes. The increased H+ efflux from axolotl Müller cells induced by extracellular ATP required activation of metabotropic purinergic receptors and was dependent upon calcium released from internal stores. We further found that the ATP-evoked increase in H+ efflux from Müller cells of both tiger salamander and axolotl were sensitive to pharmacological agents known to interrupt calmodulin and protein kinase C (PKC) activity: chlorpromazine (CLP), trifluoperazine (TFP), and W-7 (all calmodulin inhibitors) and chelerythrine, a PKC inhibitor, all attenuated ATP-elicited increases in H+ efflux. ATP-initiated H+ fluxes of axolotl Müller cells were also significantly reduced by amiloride, suggesting a significant contribution by sodium-hydrogen exchangers (NHEs). In addition, α-cyano-4-hydroxycinnamate (4-cin), a monocarboxylate transport (MCT) inhibitor, also reduced the ATP-induced increase in H+ efflux in both axolotl and tiger salamander Müller cells, and when combined with amiloride, abolished ATP-evoked increase in H+ efflux. These data suggest that axolotl Müller cells are likely to be an excellent model system to understand the cell-signaling pathways regulating H+ release from glia and the role this may play in modulating neuronal signaling.NEW & NOTEWORTHY Glial cells are a key structural part of the tripartite synapse and have been suggested to regulate synaptic transmission, but the regulatory mechanisms remain unclear. We show that extracellular ATP, a potent glial cell activator, induces H+ efflux from axolotl retinal Müller (glial) cells through a calcium-dependent pathway that is likely to involve calmodulin, PKC, Na+/H+ exchange, and monocarboxylate transport, and suggest that such H+ release may play a key role in modulating neuronal transmission.
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Affiliation(s)
- Matthew A Kreitzer
- Department of Biology, Indiana Wesleyan University, Marion, Indiana, United States
| | - Mason Vredeveld
- Department of Biology, Indiana Wesleyan University, Marion, Indiana, United States
| | - Kaleb Tinner
- Department of Biology, Indiana Wesleyan University, Marion, Indiana, United States
| | - Alyssa M Powell
- Department of Biology, Indiana Wesleyan University, Marion, Indiana, United States
| | - Adam W Schantz
- Department of Biology, Indiana Wesleyan University, Marion, Indiana, United States
| | - Rachel Leininger
- Department of Biology, Indiana Wesleyan University, Marion, Indiana, United States
| | - Rajapone Merillat
- Department of Biology, Indiana Wesleyan University, Marion, Indiana, United States
| | - Michael W Gongwer
- Department of Biology, Indiana Wesleyan University, Marion, Indiana, United States
| | - Boriana K Tchernookova
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois, United States
| | - Robert Paul Malchow
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois, United States
- Department of Psychology, College of the Holy Cross, Worcester, Massachusetts, United States
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Hool SA, Jeng J, Jagger DJ, Marcotti W, Ceriani F. Age-related changes in P2Y receptor signalling in mouse cochlear supporting cells. J Physiol 2023; 601:4375-4395. [PMID: 37715703 PMCID: PMC10952729 DOI: 10.1113/jp284980] [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: 05/04/2023] [Accepted: 08/16/2023] [Indexed: 09/18/2023] Open
Abstract
Our sense of hearing depends on the function of a specialised class of sensory cells, the hair cells, which are found in the organ of Corti of the mammalian cochlea. The unique physiological environment in which these cells operate is maintained by a syncitium of non-sensory supporting cells, which are crucial for regulating cochlear physiology and metabolic homeostasis. Despite their importance for cochlear function, the role of these supporting cells in age-related hearing loss, the most common sensory deficit in the elderly, is poorly understood. Here, we investigated the age-related changes in the expression and function of metabotropic purinergic receptors (P2Y1 , P2Y2 and P2Y4 ) in the supporting cells of the cochlear apical coil. Purinergic signalling in supporting cells is crucial during the development of the organ of Corti and purinergic receptors are known to undergo changes in expression during ageing in several tissues. Immunolabelling and Ca2+ imaging experiments revealed a downregulation of P2Y receptor expression and a decrease of purinergic-mediated calcium responses after early postnatal stages in the supporting cells. An upregulation of P2Y receptor expression was observed in the aged cochlea when compared to 1 month-old adults. The aged mice also had significantly larger calcium responses and displayed calcium oscillations during prolonged agonist applications. We conclude that supporting cells in the aged cochlea upregulate P2Y2 and P2Y4 receptors and display purinergic-induced Ca2+ responses that mimic those observed during pre-hearing stages of development, possibly aimed at limiting or preventing further damage to the sensory epithelium. KEY POINTS: Age-related hearing loss is associated with lower hearing sensitivity and decreased ability to understand speech. We investigated age-related changes in the expression and function of metabotropic purinergic (P2Y) receptors in cochlear non-sensory supporting cells of mice displaying early-onset (C57BL/6N) and late-onset (C3H/HeJ) hearing loss. The expression of P2Y1 , P2Y2 and P2Y4 receptors in the supporting cells decreased during cochlear maturation, but that of P2Y2 and P2Y4 was upregulated in the aged cochlea. P2Y2 and P2Y4 receptors were primarily responsible for the ATP-induced Ca2+ responses in the supporting cells. The degree of purinergic expression upregulation in aged supporting cells mirrored hearing loss progression in the different mouse strains. We propose that the upregulation of purinergic-mediated signalling in the aged cochlea is subsequent to age-related changes in the hair cells and may act as a protective mechanism to limit or to avoid further damage to the sensory epithelium.
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Affiliation(s)
- Sarah A. Hool
- School of BiosciencesUniversity of SheffieldSheffieldUK
| | - Jing‐Yi Jeng
- School of BiosciencesUniversity of SheffieldSheffieldUK
| | | | - Walter Marcotti
- School of BiosciencesUniversity of SheffieldSheffieldUK
- Neuroscience InstituteUniversity of SheffieldSheffieldUK
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Yu H, Zhong H, Sun J, Li N, Chen J, Shen B, Huang P, Shen X, Huang S, Zhong Y. Molecular signaling from microglia impacts macroglia autophagy and neurons survival in glaucoma. iScience 2023; 26:106839. [PMID: 37250793 PMCID: PMC10213002 DOI: 10.1016/j.isci.2023.106839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 02/01/2023] [Accepted: 05/04/2023] [Indexed: 05/31/2023] Open
Abstract
Interactions between microglia and macroglia play important roles in the neurodegeneration of the central nervous system and so is the situation between microglia and Müller cells in retina neurodegenerations like glaucoma. This study focuses on the roles of microglia-derived osteopontin (OPN) in impacting Müller cells and retinal ganglion cells (RGCs). Rat model and cell pressurization culture were used to simulate glaucoma scenarios. Animals were differently treated with anti-OPN, suppressors of OPN receptors (Itgαvβ3/CD44) or microglia inhibitor minocycline, while isolated retinal Müller cells were accordingly treated with conditioned media from microglia culture pretreated with pressuring, overexpression-OPN, SiR-OPN, or minocycline. SB203580 was introduced to explore the role of p38 MAPK signaling pathway. Results revealed microglia may secret OPN to impact Müller cells' autophagy and RGCs survival via binding to Itgαvβ3/CD44 receptors in glaucomatous neurodegeneration with involvement of p38 MAPK pathway. This discovery may benefit understanding neurodegenerative disorders and exploring therapeutics.
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Affiliation(s)
- Huan Yu
- Department of Ophthalmology, Ruijin Hospital Affiliated Medical School, Shanghai Jiaotong University, 197 Ruijin Er Road, Shanghai 200025, China
| | - Huimin Zhong
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People’s Hospital), Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China
| | - Jun Sun
- Department of Ophthalmology, Ruijin Hospital Affiliated Medical School, Shanghai Jiaotong University, 197 Ruijin Er Road, Shanghai 200025, China
| | - Na Li
- Department of Ophthalmology, Ruijin Hospital Affiliated Medical School, Shanghai Jiaotong University, 197 Ruijin Er Road, Shanghai 200025, China
| | - Junjue Chen
- Department of Ophthalmology, Ruijin Hospital Affiliated Medical School, Shanghai Jiaotong University, 197 Ruijin Er Road, Shanghai 200025, China
| | - Bingqiao Shen
- Department of Ophthalmology, Ruijin Hospital Affiliated Medical School, Shanghai Jiaotong University, 197 Ruijin Er Road, Shanghai 200025, China
| | - Ping Huang
- Department of Orthopaedics, Shanghai Key Laboratory for Bone and Joint Diseases, Shanghai Institute of Traumatology and Orthopaedics, Ruijin Hospital Affiliated Medical School, Shanghai Jiaotong University, 197 Ruijin Er Road, Shanghai 200025, China
| | - Xi Shen
- Department of Ophthalmology, Ruijin Hospital Affiliated Medical School, Shanghai Jiaotong University, 197 Ruijin Er Road, Shanghai 200025, China
| | - Shouyue Huang
- Department of Ophthalmology, Ruijin Hospital Affiliated Medical School, Shanghai Jiaotong University, 197 Ruijin Er Road, Shanghai 200025, China
| | - Yisheng Zhong
- Department of Ophthalmology, Ruijin Hospital Affiliated Medical School, Shanghai Jiaotong University, 197 Ruijin Er Road, Shanghai 200025, China
- Department of Ophthalmology, Zhoushan Branch of Ruijin Hospital Affiliated Medical School, Shanghai Jiaotong University, Zhoushan, China
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Cheng C, Ma J, Lu X, Zhang P, Wang X, Guo L, Li P, Wei Y, Li GL, Gao X, Zhang Y, Chai R, Li H, Sun S. P2X7 receptor is required for the ototoxicity caused by aminoglycoside in developing cochlear hair cells. Neurobiol Dis 2023:106176. [PMID: 37263384 DOI: 10.1016/j.nbd.2023.106176] [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: 04/03/2023] [Revised: 05/27/2023] [Accepted: 05/27/2023] [Indexed: 06/03/2023] Open
Abstract
Aminoglycoside antibiotics (AGAs) are widely used in life-threatening infections, but they accumulate in cochlear hair cells (HCs) and result in hearing loss. Increases in adenosine triphosphate (ATP) concentrations and P2X7 receptor expression were observed after neomycin treatment. Here, we demonstrated that P2X7 receptor, which is a non-selective cation channel that is activated by high ATP concentrations, may participate in the process through which AGAs enter hair cells. Using transgenic knockout mice, we found that P2X7 receptor deficiency protects HCs against neomycin-induced injury in vitro and in vivo. Subsequently, we used fluorescent gentamicin-Fluor 594 to study the uptake of AGAs and found fluorescence labeling in wild-type mice but not in P2rx7-/- mice in vitro. In addition, knocking-out P2rx7 did not significantly alter the HC count and auditory signal transduction, but it did inhibit mitochondria-dependent oxidative stress and apoptosis in the cochlea after neomycin exposure. We thus conclude that the P2X7 receptor may be linked to the entry of AGAs into HCs and is likely to be a therapeutic target for auditory HC protection.
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Affiliation(s)
- Cheng Cheng
- Department of Otolaryngology Head and Neck Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical School, Jiangsu Provincial Key Medical Discipline (Laboratory), No.321 Zhongshan Road,Nanjing 210008, China
| | - Jiaoyao Ma
- ENT institute and Otorhinolaryngology Department of Eye & ENT Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai 200031, China
| | - Xiaoling Lu
- ENT institute and Otorhinolaryngology Department of Eye & ENT Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai 200031, China
| | - Panpan Zhang
- State Key Laboratory of Digital Medical Engineering, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing 210096, China
| | - Xiaohan Wang
- State Key Laboratory of Digital Medical Engineering, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing 210096, China
| | - Luo Guo
- ENT institute and Otorhinolaryngology Department of Eye & ENT Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai 200031, China
| | - Peifan Li
- ENT institute and Otorhinolaryngology Department of Eye & ENT Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai 200031, China
| | - Ying Wei
- Department of Integrative Medicine, Huashan Hospital, Fudan University, Shanghai, China; Institutes of Integrative Medicine, Fudan University, Shanghai, China
| | - Geng-Lin Li
- ENT institute and Otorhinolaryngology Department of Eye & ENT Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai 200031, China
| | - Xia Gao
- Department of Otolaryngology Head and Neck Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical School, Jiangsu Provincial Key Medical Discipline (Laboratory), No.321 Zhongshan Road,Nanjing 210008, China
| | - Yuqiu Zhang
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China.
| | - Renjie Chai
- State Key Laboratory of Digital Medical Engineering, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing 210096, China; Co-Innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China; Department of Otolaryngology Head and Neck Surgery, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China; Institute for Stem Cell and Regeneration, Chinese Academy of Science, Beijing, China; Beijing Key Laboratory of Neural Regeneration and Repair, Capital Medical University, 100069 Beijing, China.
| | - Huawei Li
- ENT institute and Otorhinolaryngology Department of Eye & ENT Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai 200031, China; Fudan University School of Basic Medical Sciences, NHC Key Laboratory of Hearing Medicine, Institutes of Biomedical Sciences, Shanghai, China; State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China.
| | - Shan Sun
- ENT institute and Otorhinolaryngology Department of Eye & ENT Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai 200031, China.
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D'Amico D, Barone R, Di Felice V, Ances B, Prideaux B, Eugenin EA. Chronic brain damage in HIV-infected individuals under antiretroviral therapy is associated with viral reservoirs, sulfatide release, and compromised cell-to-cell communication. Cell Mol Life Sci 2023; 80:116. [PMID: 37016051 PMCID: PMC11071786 DOI: 10.1007/s00018-023-04757-0] [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: 07/01/2022] [Revised: 03/11/2023] [Accepted: 03/13/2023] [Indexed: 04/06/2023]
Abstract
HIV infection has become a chronic and manageable disease due to the effective use of antiretroviral therapies (ART); however, several chronic aging-related comorbidities, including cognitive impairment, remain a major public health issue. However, these mechanisms are unknown. Here, we identified that glial and myeloid viral reservoirs are associated with local myelin damage and the release of several myelin components, including the lipid sulfatide. Soluble sulfatide compromised gap junctional communication and calcium wave coordination, essential for proper cognition. We propose that soluble sulfatide could be a potential biomarker and contributor to white matter compromise observed in HIV-infected individuals even in the current ART era.
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Affiliation(s)
- Daniela D'Amico
- Department of Neurobiology, The University of Texas Medical Branch (UTMB), Research Building 17, Fifth Floor, 11Th Street, Galveston, TX, 77555, USA
- Department of Biomedicine, Neuroscience, and Advanced Diagnostics (BiND), University of Palermo, Palermo, Italy
| | - Rosario Barone
- Department of Biomedicine, Neuroscience, and Advanced Diagnostics (BiND), University of Palermo, Palermo, Italy
| | - Valentina Di Felice
- Department of Biomedicine, Neuroscience, and Advanced Diagnostics (BiND), University of Palermo, Palermo, Italy
| | - Beau Ances
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, USA
| | - Brendan Prideaux
- Department of Neurobiology, The University of Texas Medical Branch (UTMB), Research Building 17, Fifth Floor, 11Th Street, Galveston, TX, 77555, USA.
| | - Eliseo A Eugenin
- Department of Neurobiology, The University of Texas Medical Branch (UTMB), Research Building 17, Fifth Floor, 11Th Street, Galveston, TX, 77555, USA.
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9
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Aten S, Du Y, Taylor O, Dye C, Collins K, Thomas M, Kiyoshi C, Zhou M. Chronic Stress Impairs the Structure and Function of Astrocyte Networks in an Animal Model of Depression. Neurochem Res 2023; 48:1191-1210. [PMID: 35796915 PMCID: PMC9823156 DOI: 10.1007/s11064-022-03663-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 06/18/2022] [Indexed: 01/11/2023]
Abstract
Now astrocytes appear to be the key contributors to the pathophysiology of major depression. Evidence in rodents shows that chronic stress is associated with a decreased expression of astrocytic GFAP-immunoreactivity within the cortex in addition to changes in the complexity and length of astrocyte processes. Furthermore, postmortem brains of individuals with depression have revealed a decrease in astrocyte density. Notably, astrocytes are extensively coupled to one another through gap junctions to form a network, or syncytium, and we have previously demonstrated that syncytial isopotentiality is a mechanism by which astrocytes function as an efficient system with respect to brain homeostasis. Interestingly, the question of how astrocyte network function changes following chronic stress is yet to be elucidated. Here, we sought to examine the effects of chronic stress on network-level astrocyte (dys)function. Using a transgenic aldh1l1-eGFP astrocyte reporter mouse, a six-week unpredictable chronic mild stress (UCMS) paradigm as a rodent model of major depression, and immunohistochemical approaches, we show that the morphology of individual astrocytes is altered by chronic stress exposure. Additionally, in astrocyte syncytial isopotentiality measurement, we found that UCMS impairs the syncytial coupling strength of astrocytes within the hippocampus and prefrontal cortex-two brain regions that have been implicated in the regulation of mood. Together, these findings reveal that chronic stress leads to astrocyte atrophy and impaired gap junction coupling, raising the prospect that both individual and network-level astrocyte functionality are important in the etiology of major depression and other neuropsychiatric disorders.
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Affiliation(s)
- Sydney Aten
- Department of Neuroscience, Ohio State University Wexner Medical Center, Graves Hall, Rm 4066C, 333 W. 10th Ave, Columbus, OH, 43210, USA
- Department of Neurology, Division of Sleep Medicine, and Program in Neuroscience, Harvard Medical School, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - Yixing Du
- Department of Neuroscience, Ohio State University Wexner Medical Center, Graves Hall, Rm 4066C, 333 W. 10th Ave, Columbus, OH, 43210, USA
| | - Olivia Taylor
- Department of Neuroscience, Ohio State University Wexner Medical Center, Graves Hall, Rm 4066C, 333 W. 10th Ave, Columbus, OH, 43210, USA
| | - Courtney Dye
- Department of Neuroscience, Ohio State University Wexner Medical Center, Graves Hall, Rm 4066C, 333 W. 10th Ave, Columbus, OH, 43210, USA
| | - Kelsey Collins
- Department of Neuroscience, Ohio State University Wexner Medical Center, Graves Hall, Rm 4066C, 333 W. 10th Ave, Columbus, OH, 43210, USA
| | - Matthew Thomas
- Department of Neuroscience, Ohio State University Wexner Medical Center, Graves Hall, Rm 4066C, 333 W. 10th Ave, Columbus, OH, 43210, USA
| | - Conrad Kiyoshi
- Department of Neuroscience, Ohio State University Wexner Medical Center, Graves Hall, Rm 4066C, 333 W. 10th Ave, Columbus, OH, 43210, USA
- Northern Marianas College, Saipan, MP, USA
| | - Min Zhou
- Department of Neuroscience, Ohio State University Wexner Medical Center, Graves Hall, Rm 4066C, 333 W. 10th Ave, Columbus, OH, 43210, USA.
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10
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Zhong S, Kiyoshi CM, Du Y, Wang W, Luo Y, Wu X, Taylor AT, Ma B, Aten S, Liu X, Zhou M. Genesis of a functional astrocyte syncytium in the developing mouse hippocampus. Glia 2023; 71:1081-1098. [PMID: 36598109 PMCID: PMC10777263 DOI: 10.1002/glia.24327] [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: 09/17/2022] [Revised: 12/03/2022] [Accepted: 12/15/2022] [Indexed: 01/05/2023]
Abstract
Astrocytes are increasingly shown to operate as an isopotential syncytium in brain function. Protoplasmic astrocytes acquire this ability to functionally go beyond the single-cell level by evolving into a spongiform morphology, cytoplasmically connecting into a syncytium, and expressing a high density of K+ conductance. However, none of these cellular/functional features exist in neonatal newborn astrocytes, which imposes a basic question of when a functional syncytium evolves in the developing brain. Our results show that the spongiform morphology of individual astrocytes and their spatial organization all reach stationary levels by postnatal day (P) 15 in the hippocampal CA1 region. Functionally, astrocytes begin to uniformly express a mature level of passive K+ conductance by P11. We next used syncytial isopotentiality measurement to monitor the maturation of the astrocyte syncytium. In uncoupled P1 astrocytes, the substitution of endogenous K+ by a Na+ -electrode solution ([Na+ ]p ) resulted in the total elimination of the physiological membrane potential (VM ), and outward K+ conductance as predicted by the Goldman-Hodgkin-Katz (GHK) equation. As more astrocytes are coupled to each other through gap junctions during development, the [Na+ ]p -induced loss of physiological VM and the outward K+ conductance is progressively compensated by the neighboring astrocytes. By P15, a stably established syncytial isopotentiality (-73 mV), and a fully compensated outward K+ conductance appeared in all [Na+ ]p -recorded astrocytes. Thus, in view of the developmental timeframe wherein a singular syncytium is anatomically and functionally established for intra-syncytium K+ equilibration, an astrocyte syncytium becomes fully operational at P15 in the mouse hippocampus.
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Affiliation(s)
- Shiying Zhong
- Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
- Department of Neurology, Shanghai 10Hospital of Tongji University, School of Medicine, Shanghai, 200072, China
| | - Conrad M. Kiyoshi
- Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
| | - Yixing Du
- Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
| | - Wei Wang
- Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
- Department of Physiology, Tongji Medical College, Wuhan, 430030, China
| | - Yumeng Luo
- Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
| | - Xiao Wu
- Department of Neurology, Wuhan First Hospital, Wuhan 430022, China
| | - Anne T. Taylor
- Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
| | - Baofeng Ma
- Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
| | - Sydney Aten
- Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
| | - Xueyuan Liu
- Department of Neurology, Shanghai 10Hospital of Tongji University, School of Medicine, Shanghai, 200072, China
| | - Min Zhou
- Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
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11
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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: 13] [Impact Index Per Article: 13.0] [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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12
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Nanotopography and Microconfinement Impact on Primary Hippocampal Astrocyte Morphology, Cytoskeleton and Spontaneous Calcium Wave Signalling. Cells 2023; 12:cells12020293. [PMID: 36672231 PMCID: PMC9856934 DOI: 10.3390/cells12020293] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 12/19/2022] [Accepted: 01/10/2023] [Indexed: 01/15/2023] Open
Abstract
Astrocytes' organisation affects the functioning and the fine morphology of the brain, both in physiological and pathological contexts. Although many aspects of their role have been characterised, their complex functions remain, to a certain extent, unclear with respect to their contribution to brain cell communication. Here, we studied the effects of nanotopography and microconfinement on primary hippocampal rat astrocytes. For this purpose, we fabricated nanostructured zirconia surfaces as homogenous substrates and as micrometric patterns, the latter produced by a combination of an additive nanofabrication and micropatterning technique. These engineered substrates reproduce both nanotopographical features and microscale geometries that astrocytes encounter in their natural environment, such as basement membrane topography, as well as blood vessels and axonal fibre topology. The impact of restrictive adhesion manifests in the modulation of several cellular properties of single cells (morphological and actin cytoskeletal changes) and the network organisation and functioning. Calcium wave signalling was observed only in astrocytes grown in confined geometries, with an activity enhancement in cells forming elongated agglomerates with dimensions typical of blood vessels or axon fibres. Our results suggest that calcium oscillation and wave propagation are closely related to astrocytic morphology and actin cytoskeleton organisation.
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13
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Li J, Feng P, Zhao L, Chen J, Du M, Song J, Wu Y. Transition behavior of the seizure dynamics modulated by the astrocyte inositol triphosphate noise. CHAOS (WOODBURY, N.Y.) 2022; 32:113121. [PMID: 36456345 DOI: 10.1063/5.0124123] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2022] [Accepted: 10/17/2022] [Indexed: 06/17/2023]
Abstract
Epilepsy is a neurological disorder with recurrent seizures, which convey complex dynamical characteristics including chaos and randomness. Until now, the underlying mechanism has not been fully elucidated, especially the bistable property beneath the epileptic random induction phenomena in certain conditions. Inspired by the recent finding that astrocyte GTPase-activating protein (G-protein)-coupled receptors could be involved in stochastic epileptic seizures, we proposed a neuron-astrocyte network model, incorporating the noise of the astrocytic second messenger, inositol triphosphate (IP3) that is modulated by G-protein-coupled receptor activation. Based on this model, we have statistically analyzed the transitions of epileptic seizures by performing repeatable simulation trials. Our simulation results show that the increase in the IP3 noise intensity induces depolarization-block epileptic seizures together with an increase in neuronal firing frequency, consistent with corresponding experiments. Meanwhile, the bistable states of the seizure dynamics were present under certain noise intensities, during which the neuronal firing pattern switches between regular sparse spiking and epileptic seizure states. This random presence of epileptic seizures is absent when the noise intensity continues to increase, accompanying with an increase in the epileptic depolarization block duration. The simulation results also shed light on the fact that calcium signals in astrocytes play significant roles in the pattern formations of the epileptic seizure. Our results provide a potential pathway for understanding the epileptic randomness in certain conditions.
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Affiliation(s)
- Jiajia Li
- College of Information and Control Engineering, Xi'an University of Architecture and Technology, Shaanxi, Xi'an 710055, China
| | - Peihua Feng
- State Key Laboratory for Strength and Vibration of Mechanical Structures, National Demonstration Center for Experimental Mechanics Education, School of Aerospace Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Liang Zhao
- College of Information and Control Engineering, Xi'an University of Architecture and Technology, Shaanxi, Xi'an 710055, China
| | - Junying Chen
- College of Information and Control Engineering, Xi'an University of Architecture and Technology, Shaanxi, Xi'an 710055, China
| | - Mengmeng Du
- School of Mathematics and Data Science, Shaanxi University of Science and Technology, Xi'an 710021, China
| | - Jian Song
- Department of Neurosurgery, Wuhan General Hospital of PLA, Wuhan 430070, China
| | - Ying Wu
- State Key Laboratory for Strength and Vibration of Mechanical Structures, National Demonstration Center for Experimental Mechanics Education, School of Aerospace Engineering, Xi'an Jiaotong University, Xi'an 710049, China
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14
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Astrocytic Piezo1-mediated mechanotransduction determines adult neurogenesis and cognitive functions. Neuron 2022; 110:2984-2999.e8. [PMID: 35963237 DOI: 10.1016/j.neuron.2022.07.010] [Citation(s) in RCA: 43] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 05/31/2022] [Accepted: 07/12/2022] [Indexed: 12/12/2022]
Abstract
Adult brain activities are generally believed to be dominated by chemical and electrical transduction mechanisms. However, the importance of mechanotransduction mediated by mechano-gated ion channels in brain functions is less appreciated. Here, we show that the mechano-gated Piezo1 channel is expressed in the exploratory processes of astrocytes and utilizes its mechanosensitivity to mediate mechanically evoked Ca2+ responses and ATP release, establishing Piezo1-mediated mechano-chemo transduction in astrocytes. Piezo1 deletion in astrocytes causes a striking reduction of hippocampal volume and brain weight and severely impaired (but ATP-rescuable) adult neurogenesis in vivo, and it abolishes ATP-dependent potentiation of neural stem cell (NSC) proliferation in vitro. Piezo1-deficient mice show impaired hippocampal long-term potentiation (LTP) and learning and memory behaviors. By contrast, overexpression of Piezo1 in astrocytes sufficiently enhances mechanotransduction, LTP, and learning and memory performance. Thus, astrocytes utilize Piezo1-mediated mechanotransduction mechanisms to robustly regulate adult neurogenesis and cognitive functions, conceptually highlighting the importance of mechanotransduction in brain structure and function.
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15
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Jo AO, Lakk M, Rudzitis CN, Križaj D. TRPV4 and TRPC1 channels mediate the response to tensile strain in mouse Müller cells. Cell Calcium 2022; 104:102588. [PMID: 35398674 PMCID: PMC9119919 DOI: 10.1016/j.ceca.2022.102588] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 03/10/2022] [Accepted: 04/01/2022] [Indexed: 11/24/2022]
Abstract
Müller glia, a pillar of metabolic, volume regulatory and immune/inflammatory signaling in the mammalian retina, are among the earliest responders to mechanical stressors in the eye. Ocular trauma, edema, detachment and glaucoma evoke early inflammatory activation of Müller cells yet the identity of their mechanotransducers and signaling mechanisms downstream remains unknown. Here, we investigate expression of genes that encode putative stretch-activated calcium channels (SACs) in mouse Müller cells and study their responses to dynamical tensile loading in cells loaded with a calcium indicator dye. Transcript levels in purified glia were Trpc1>Piezo1>Trpv2>Trpv4>>Trpv1>Trpa1. Cyclic radial deformation of matrix-coated substrates produced dose-dependent increases in [Ca2+]i that were suppressed by the TRPV4 channel antagonist HC-067047 and by ablation of the Trpv4 gene. Stretch-evoked calcium responses were also reduced by knockdown and pharmacological inhibition of TRPC1 channels whereas the TRPV2 inhibitor tranilast had no effect. These data demonstrate that Müller cells are intrinsically mechanosensitive, with the response to tensile loading mediated through synergistic activation of TRPV4 and TRPC1 channels. Coupling between mechanical stress and Müller Ca2+ homeostasis has treatment implications, since many neuronal injury paradigms in the retina involve calcium dysregulation associated with inflammatory and immune signaling.
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Affiliation(s)
- Andrew O Jo
- Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT 84132
| | - Monika Lakk
- Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT 84132
| | - Christopher N Rudzitis
- Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT 84132; Interdepartmental Program in Neuroscience
| | - David Križaj
- Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT 84132; Interdepartmental Program in Neuroscience; Department of Neurobiology, University of Utah, Salt Lake City, UT 84112; Department of Bioengineering, University of Utah, Salt Lake City, UT 84112.
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16
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Karadayi R, Mazzocco J, Leclere L, Buteau B, Gregoire S, Belloir C, Koudsi M, Bessard P, Bizeau JB, Dubus E, Fenech C, Briand L, Bretillon L, Bron AM, Fioramonti X, Acar N. Plasmalogens Regulate Retinal Connexin 43 Expression and Müller Glial Cells Gap Junction Intercellular Communication and Migration. Front Cell Dev Biol 2022; 10:864599. [PMID: 35433704 PMCID: PMC9009447 DOI: 10.3389/fcell.2022.864599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 03/16/2022] [Indexed: 11/13/2022] Open
Abstract
Plasmalogens are a specific glycerophospholipid subtype characterized by a vinyl-ether bound at their sn-1 moiety. Their biosynthesis is initiated in the peroxisome by dihydroxyacetone phosphate-acyltransferase (DHAPAT), which is encoded by the DAPAT gene. Previous studies have shown that plasmalogen-deficient mice exhibit major physiological dysfunctions including several eye defects, among which abnormal vascular development of the retina and a reactive activation of macroglial Müller cells. Interestingly, plasmalogen deficiency in mice is also associated with a reduced expression of brain connexin 43 (Cx43). Cx43 is the main connexin subtype of retinal glial cells and is involved in several cellular mechanisms such as calcium-based gap junction intercellular communication (GJIC) or cell migration. Thus, the aim of our work was 1) to confirm the alteration of Cx43 expression in the retina of plasmalogen-deficient DAPAT−/- mice and 2) to investigate whether plasmalogens are involved in crucial functions of Müller cells such as GJIC and cell migration. First, we found that plasmalogen deficiency was associated with a significant reduction of Cx43 expression in the retina of DAPAT−/- mice in vivo. Secondly, using a siRNA targeting DHAPAT in vitro, we found that a 50%-reduction of Müller cells content in plasmalogens was sufficient to significantly downregulate Cx43 expression, while increasing its phosphorylation. Furthermore, plasmalogen-depleted Müller cells exhibited several alterations in ATP-induced GJIC, such as calcium waves of higher amplitude that propagated slower to neighboring cells, including astrocytes. Finally, in vitro plasmalogen depletion was also associated with a significant downregulation of Müller cells migration. Taken together, these data confirm that plasmalogens are critical for the regulation of Cx43 expression and for characteristics of retinal Müller glial cells such as GJIC and cell migration.
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Affiliation(s)
- Rémi Karadayi
- Eye and Nutrition Research Group, CSGA, Université de Bourgogne Franche-Comté, Dijon, France
| | - Julie Mazzocco
- Eye and Nutrition Research Group, CSGA, Université de Bourgogne Franche-Comté, Dijon, France
| | - Laurent Leclere
- Eye and Nutrition Research Group, CSGA, Université de Bourgogne Franche-Comté, Dijon, France
| | - Bénédicte Buteau
- Eye and Nutrition Research Group, CSGA, Université de Bourgogne Franche-Comté, Dijon, France
| | - Stéphane Gregoire
- Eye and Nutrition Research Group, CSGA, Université de Bourgogne Franche-Comté, Dijon, France
| | - Christine Belloir
- Taste and Olfaction Research Group, CSGA, Université de Bourgogne Franche-Comté, Dijon, France
| | - Mounzer Koudsi
- Eye and Nutrition Research Group, CSGA, Université de Bourgogne Franche-Comté, Dijon, France
| | - Pauline Bessard
- Eye and Nutrition Research Group, CSGA, Université de Bourgogne Franche-Comté, Dijon, France
| | - Jean-Baptiste Bizeau
- Eye and Nutrition Research Group, CSGA, Université de Bourgogne Franche-Comté, Dijon, France
| | - Elisabeth Dubus
- Eye and Nutrition Research Group, CSGA, Université de Bourgogne Franche-Comté, Dijon, France
| | - Claire Fenech
- Brain Nutrient Sensing and Energy Homeostasis, CSGA, Université de Bourgogne Franche-Comté, Dijon, France
| | - Loïc Briand
- Taste and Olfaction Research Group, CSGA, Université de Bourgogne Franche-Comté, Dijon, France
| | - Lionel Bretillon
- Eye and Nutrition Research Group, CSGA, Université de Bourgogne Franche-Comté, Dijon, France
| | - Alain M. Bron
- Eye and Nutrition Research Group, CSGA, Université de Bourgogne Franche-Comté, Dijon, France
- Department of Ophthalmology, University Hospital, Dijon, France
| | | | - Niyazi Acar
- Eye and Nutrition Research Group, CSGA, Université de Bourgogne Franche-Comté, Dijon, France
- *Correspondence: Niyazi Acar,
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17
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Ozgur M, Özyurt MG, Arkan S, Cavdar S. The Effects of Optogenetic Activation of Astrocytes on Spike-and-Wave Discharges in Genetic Absence Epileptic Rats. Ann Neurosci 2022; 29:53-61. [PMID: 35875425 PMCID: PMC9305907 DOI: 10.1177/09727531211072423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 11/29/2021] [Indexed: 11/16/2022] Open
Abstract
Background: Absence seizures (petit mal seizures) are characterized by a brief loss of consciousness without loss of postural tone. The disease is diagnosed by an electroencephalogram (EEG) showing spike–wave discharges (SWD) caused by hypersynchronous thalamocortical (TC) oscillations. There has been an explosion of research highlighting the role of astrocytes in supporting and modulating neuronal activity. Despite established in vitro evidence, astrocytes’ influence on the TC network remains to be elucidated in vivo in the absence epilepsy (AE). Purpose: In this study, we investigated the role of astrocytes in the generation and modulation of SWDs. We hypothesize that disturbances in astrocytes’ function may affect the pathomechanism of AE. Methods: To direct the expression of channelrhodopsin-2 (ChR2) rAAV8-GFAP-ChR2(H134R)-EYFP or to control the effect of surgical intervention, AAV-CaMKIIa-EYFP was injected into the ventrobasal nucleus (VB) of the thalamus of 18 animals. After four weeks following the injection, rats were stimulated using blue light (~473 nm) and, simultaneously, the electrophysiological activity of the frontal cortical neurons was recorded for three consecutive days. The animals were then perfused, and the brain tissue was analyzed by confocal microscopy. Results: A significant increase in the duration of SWD without affecting the number of SWD in genetic absence epileptic rats from Strasbourg (GAERS) compared to control injections was observed. The duration of the SWD was increased from 12.50 ± 4.41 s to 17.44 ± 6.07 following optogenetic stimulation in GAERS. The excitation of the astrocytes in Wistar Albino Glaxo Rijswijk (WAG-Rij) did not change the duration of SWD; however, stimulation resulted in a significant increase in the number of SWD from 18.52 ± 11.46 bursts/30 min to 30.17 ± 18.43 bursts/30 min. Whereas in control injection, the duration and the number of SWDs were similar at pre- and poststimulus. Both the background and poststimulus average firing rates of the SWD in WAG-Rij were significantly higher than the firing recorded in GAERS. Conclusion: These findings suggest that VB astrocytes play a role in modulating the SWD generation in both rat models with distinct mechanisms and can present an essential target for the possible therapeutic approach for AE.
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Affiliation(s)
- Merve Ozgur
- Graduate School of Health Sciences, Division of Neuroscience, Koc University, Istanbul Turkey
- Department of Anatomy, Faculty of Medicine, Izmir University of Economics, Izmir, Turkey
- Department of Anatomy, Koç University School of Medicine, Istanbul, Turkey
| | - Mustafa Görkem Özyurt
- Department of Anatomy, Koç University School of Medicine, Istanbul, Turkey
- Graduate School of Sciences and Engineering, Koç University, Istanbul, Turkey
| | - Sertan Arkan
- Queen Square Institute of Neurology, University College London, London, United Kingdom
| | - Safiye Cavdar
- Department of Experimental Medical Science, Molecular Neurobiology Unit, Lund University, Lund, Sweden
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18
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Xu MX, Zhao GL, Hu X, Zhou H, Li SY, Li F, Miao Y, Lei B, Wang Z. P2X7/P2X4 Receptors Mediate Proliferation and Migration of Retinal Microglia in Experimental Glaucoma in Mice. Neurosci Bull 2022; 38:901-915. [PMID: 35254644 PMCID: PMC9352844 DOI: 10.1007/s12264-022-00833-w] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 12/13/2021] [Indexed: 10/18/2022] Open
Abstract
Microglia are involved in the inflammatory response and retinal ganglion cell damage in glaucoma. Here, we investigated how microglia proliferate and migrate in a mouse model of chronic ocular hypertension (COH). In COH retinas, the microglial proliferation that occurred was inhibited by the P2X7 receptor (P2X7R) blocker BBG or P2X7R knockout, but not by the P2X4R blocker 5-BDBD. Treatment of primary cultured microglia with BzATP, a P2X7R agonist, mimicked the effects of cell proliferation and migration in COH retinas through the intracellular MEK/ERK signaling pathway. Transwell migration assays showed that the P2X4R agonist CTP induced microglial migration, which was completely blocked by 5-BDBD. In vivo and in vitro experiments demonstrated that ATP, released from activated Müller cells through connexin43 hemichannels, acted on P2X7R to induce microglial proliferation, and acted on P2X4R/P2X7R (mainly P2X4R) to induce microglial migration. Our results suggest that inhibiting the interaction of Müller cells and microglia may attenuate microglial proliferation and migration in glaucoma.
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19
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Hartmann DA, Coelho-Santos V, Shih AY. Pericyte Control of Blood Flow Across Microvascular Zones in the Central Nervous System. Annu Rev Physiol 2022; 84:331-354. [PMID: 34672718 PMCID: PMC10480047 DOI: 10.1146/annurev-physiol-061121-040127] [Citation(s) in RCA: 70] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The vast majority of the brain's vascular length is composed of capillaries, where our understanding of blood flow control remains incomplete. This review synthesizes current knowledge on the control of blood flow across microvascular zones by addressing issues with nomenclature and drawing on new developments from in vivo optical imaging and single-cell transcriptomics. Recent studies have highlighted important distinctions in mural cell morphology, gene expression, and contractile dynamics, which can explain observed differences in response to vasoactive mediators between arteriole, transitional, and capillary zones. Smooth muscle cells of arterioles and ensheathing pericytes of the arteriole-capillary transitional zone control large-scale, rapid changes in blood flow. In contrast, capillary pericytes downstream of the transitional zone act on slower and smaller scales and are involved in establishing resting capillary tone and flow heterogeneity. Many unresolved issues remain, including the vasoactive mediators that activate the different pericyte types in vivo, the role of pericyte-endothelial communication in conducting signals from capillaries to arterioles, and how neurological disease affects these mechanisms.
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Affiliation(s)
- David A Hartmann
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, California, USA
| | - Vanessa Coelho-Santos
- Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, Washington, USA;
- Department of Pediatrics, University of Washington, Seattle, Washington, USA
| | - Andy Y Shih
- Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, Washington, USA;
- Department of Pediatrics, University of Washington, Seattle, Washington, USA
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
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20
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Benfey N, Foubert D, Ruthazer ES. Glia Regulate the Development, Function, and Plasticity of the Visual System From Retina to Cortex. Front Neural Circuits 2022; 16:826664. [PMID: 35177968 PMCID: PMC8843846 DOI: 10.3389/fncir.2022.826664] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 01/07/2022] [Indexed: 11/13/2022] Open
Abstract
Visual experience is mediated through a relay of finely-tuned neural circuits extending from the retina, to retinorecipient nuclei in the midbrain and thalamus, to the cortex which work together to translate light information entering our eyes into a complex and dynamic spatio-temporal representation of the world. While the experience-dependent developmental refinement and mature function of neurons in each major stage of the vertebrate visual system have been extensively characterized, the contributions of the glial cells populating each region are comparatively understudied despite important findings demonstrating that they mediate crucial processes related to the development, function, and plasticity of the system. In this article we review the mechanisms for neuron-glia communication throughout the vertebrate visual system, as well as functional roles attributed to astrocytes and microglia in visual system development and processing. We will also discuss important aspects of glial function that remain unclear, integrating the knowns and unknowns about glia in the visual system to advance new hypotheses to guide future experimental work.
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21
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Aptamer-modified biosensors to visualize neurotransmitter flux. J Neurosci Methods 2022; 365:109386. [PMID: 34653500 DOI: 10.1016/j.jneumeth.2021.109386] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 09/23/2021] [Accepted: 10/07/2021] [Indexed: 12/14/2022]
Abstract
Chemical biosensors with the capacity to continuously monitor various neurotransmitter dynamics can be powerful tools to understand complex signaling pathways in the brain. However, in vivo detection of neurochemicals is challenging for many reasons such as the rapid release and clearance of neurotransmitters in the extracellular space, or the low target analyte concentrations in a sea of interfering biomolecules. Biosensing platforms with adequate spatiotemporal resolution coupled to specific and selective receptors termed aptamers, demonstrate high potential to tackle such challenges. Herein, we review existing literature in this field. We first discuss nanoparticle-based systems, which have a simple in vitro implementation and easily interpretable results. We then examine methods employing near-infrared detection for deeper tissue imaging, hence easier translation to in vivo implementation. We conclude by reviewing live cell imaging of neurotransmitter release via aptamer-modified platforms. For each of these sensors, we discuss the associated challenges for translation to real-time in vivo neurochemical imaging. Realization of in vivo biosensors for neurotransmitters will drive future development of early prevention strategies, treatments, and therapeutics for psychiatric and neurodegenerative diseases.
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22
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Wu Z, He K, Chen Y, Li H, Pan S, Li B, Liu T, Xi F, Deng F, Wang H, Du J, Jing M, Li Y. A sensitive GRAB sensor for detecting extracellular ATP in vitro and in vivo. Neuron 2021; 110:770-782.e5. [PMID: 34942116 DOI: 10.1016/j.neuron.2021.11.027] [Citation(s) in RCA: 70] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 08/31/2021] [Accepted: 11/22/2021] [Indexed: 12/13/2022]
Abstract
The purinergic transmitter ATP (adenosine 5'-triphosphate) plays an essential role in both the central and peripheral nervous systems, and the ability to directly measure extracellular ATP in real time will increase our understanding of its physiological functions. Here, we developed a sensitive GPCR activation-based ATP sensor called GRABATP1.0, with a robust fluorescence response to extracellular ATP when expressed in several cell types. This sensor has sub-second kinetics, has ATP affinity in the range of tens of nanomolar, and can be used to localize ATP release with subcellular resolution. Using this sensor, we monitored ATP release under a variety of in vitro and in vivo conditions, including stimuli-induced and spontaneous ATP release in primary hippocampal cultures, injury-induced ATP release in a zebrafish model, and lipopolysaccharides-induced ATP-release events in individual astrocytes in the mouse cortex. Thus, the GRABATP1.0 sensor is a sensitive, versatile tool for monitoring ATP release and dynamics under both physiological and pathophysiological conditions.
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Affiliation(s)
- Zhaofa Wu
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing 100871, China; PKU-IDG/McGovern Institute for Brain Research, Beijing 100871, China.
| | - Kaikai He
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing 100871, China; PKU-IDG/McGovern Institute for Brain Research, Beijing 100871, China
| | - Yue Chen
- Chinese Institute for Brain Research, Beijing 102206, China
| | - Hongyu Li
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai 200031, China
| | - Sunlei Pan
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing 100871, China; PKU-IDG/McGovern Institute for Brain Research, Beijing 100871, China; Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Bohan Li
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing 100871, China; PKU-IDG/McGovern Institute for Brain Research, Beijing 100871, China
| | - Tingting Liu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai 200031, China
| | - Fengxue Xi
- Chinese Institute for Brain Research, Beijing 102206, China; School of Basic Medical Sciences, Capital Medical University, Beijing 100069, China
| | - Fei Deng
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing 100871, China; PKU-IDG/McGovern Institute for Brain Research, Beijing 100871, China
| | - Huan Wang
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing 100871, China; PKU-IDG/McGovern Institute for Brain Research, Beijing 100871, China
| | - Jiulin Du
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai 200031, China
| | - Miao Jing
- Chinese Institute for Brain Research, Beijing 102206, China
| | - Yulong Li
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing 100871, China; PKU-IDG/McGovern Institute for Brain Research, Beijing 100871, China; Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China; Chinese Institute for Brain Research, Beijing 102206, China.
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23
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Orts-Del'Immagine A, Dhanasekar M, Lejeune FX, Roussel J, Wyart C. A norepinephrine-dependent glial calcium wave travels in the spinal cord upon acoustovestibular stimuli. Glia 2021; 70:491-507. [PMID: 34773299 DOI: 10.1002/glia.24118] [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: 07/09/2021] [Revised: 10/27/2021] [Accepted: 11/01/2021] [Indexed: 02/06/2023]
Abstract
Although calcium waves have been widely observed in glial cells, their occurrence in vivo during behavior remains less understood. Here, we investigated the recruitment of glial cells in the hindbrain and spinal cord after acousto-vestibular (AV) stimuli triggering escape responses using in vivo population calcium imaging in larval zebrafish. We observed that gap-junction-coupled spinal glial network exhibits large and homogenous calcium increases that rose in the rostral spinal cord and propagated bi-directionally toward the spinal cord and toward the hindbrain. Spinal glial calcium waves were driven by the recruitment of neurons and in particular, of noradrenergic signaling acting through α-adrenergic receptors. Noradrenergic neurons of the medulla-oblongata (NE-MO) were revealed in the vicinity of where the calcium wave started. NE-MO were recruited upon AV stimulation and sent dense axonal projections in the rostro-lateral spinal cord, suggesting these cells could trigger the glial wave to propagate down the spinal cord. Altogether, our results revealed that a simple AV stimulation is sufficient to recruit noradrenergic neurons in the brainstem that trigger in the rostral spinal cord two massive glial calcium waves, one traveling caudally in the spinal cord and another rostrally into the hindbrain.
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Affiliation(s)
| | | | | | | | - Claire Wyart
- Institut du cerveau, Sorbonne Université, Paris, France
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24
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Malchow RP, Tchernookova BK, Choi JIV, Smith PJS, Kramer RH, Kreitzer MA. Review and Hypothesis: A Potential Common Link Between Glial Cells, Calcium Changes, Modulation of Synaptic Transmission, Spreading Depression, Migraine, and Epilepsy-H . Front Cell Neurosci 2021; 15:693095. [PMID: 34539347 PMCID: PMC8446203 DOI: 10.3389/fncel.2021.693095] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 06/25/2021] [Indexed: 01/03/2023] Open
Abstract
There is significant evidence to support the notion that glial cells can modulate the strength of synaptic connections between nerve cells, and it has further been suggested that alterations in intracellular calcium are likely to play a key role in this process. However, the molecular mechanism(s) by which glial cells modulate neuronal signaling remains contentiously debated. Recent experiments have suggested that alterations in extracellular H+ efflux initiated by extracellular ATP may play a key role in the modulation of synaptic strength by radial glial cells in the retina and astrocytes throughout the brain. ATP-elicited alterations in H+ flux from radial glial cells were first detected from Müller cells enzymatically dissociated from the retina of tiger salamander using self-referencing H+-selective microelectrodes. The ATP-elicited alteration in H+ efflux was further found to be highly evolutionarily conserved, extending to Müller cells isolated from species as diverse as lamprey, skate, rat, mouse, monkey and human. More recently, self-referencing H+-selective electrodes have been used to detect ATP-elicited alterations in H+ efflux around individual mammalian astrocytes from the cortex and hippocampus. Tied to increases in intracellular calcium, these ATP-induced extracellular acidifications are well-positioned to be key mediators of synaptic modulation. In this article, we examine the evidence supporting H+ as a key modulator of neurotransmission, review data showing that extracellular ATP elicits an increase in H+ efflux from glial cells, and describe the potential signal transduction pathways involved in glial cell-mediated H+ efflux. We then examine the potential role that extracellular H+ released by glia might play in regulating synaptic transmission within the vertebrate retina, and then expand the focus to discuss potential roles in spreading depression, migraine, epilepsy, and alterations in brain rhythms, and suggest that alterations in extracellular H+ may be a unifying feature linking these disparate phenomena.
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Affiliation(s)
- Robert Paul Malchow
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, United States
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL, United States
| | - Boriana K. Tchernookova
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, United States
| | - Ji-in Vivien Choi
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, United States
- Stritch School of Medicine, Loyola University, Maywood, IL, United States
| | - Peter J. S. Smith
- Institute for Life Sciences, University of Southampton, Highfield Campus, Southampton, United Kingdom
- Bell Center, Marine Biological Laboratory, Woods Hole, MA, United States
| | - Richard H. Kramer
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, United States
| | - Matthew A. Kreitzer
- Department of Biology, Indiana Wesleyan University, Marion, IN, United States
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25
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Townes-Anderson E, Halasz E, Wang W, Zarbin M. Coming of Age for the Photoreceptor Synapse. Invest Ophthalmol Vis Sci 2021; 62:24. [PMID: 34550300 PMCID: PMC8475281 DOI: 10.1167/iovs.62.12.24] [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: 01/07/2023] Open
Abstract
Purpose To discuss the potential contribution of rod and cone synapses to the loss of visual function in retinal injury and disease. Methods The published literature and the authors' own work were reviewed. Results Retinal detachment is used as a case study of rod spherule and cone pedicle plasticity after injury. Both rod and cone photoreceptors terminals are damaged after detachment although the structural changes observed are only partially overlapping. For second-order neurons, only those associated with rod spherules respond consistently to injury by remodeling. Examination of signaling pathways involved in plasticity of conventional synapses and in neural development has been and may continue to be productive in discovering novel therapeutic targets. Rho kinase (ROCK) inhibition is an example of therapy that may reduce synaptic damage by preserving normal synaptic structure of rod and cone cells. Conclusions We hypothesize that synaptic damage contributes to poor visual restoration after otherwise successful anatomical repair of retinal detachment. A similar situation may exist for patients with degenerative retinal disease. Thus, synaptic structure and function should be routinely studied, as this information may disclose therapeutic strategies to mitigate visual loss.
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Affiliation(s)
- Ellen Townes-Anderson
- Department of Pharmacology, Physiology, and Neuroscience, Rutgers New Jersey Medical School, Newark, New Jersey, United States
| | - Eva Halasz
- Department of Pharmacology, Physiology, and Neuroscience, Rutgers New Jersey Medical School, Newark, New Jersey, United States
| | - Weiwei Wang
- Schepens Eye Research Institute and Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard University, Boston, Massachusetts, United States
| | - Marco Zarbin
- Institute of Ophthalmology and Visual Science, Rutgers New Jersey Medical School, Newark, New Jersey, United States
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26
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De la Fuente IM, Martínez L, Carrasco-Pujante J, Fedetz M, López JI, Malaina I. Self-Organization and Information Processing: From Basic Enzymatic Activities to Complex Adaptive Cellular Behavior. Front Genet 2021; 12:644615. [PMID: 34093645 PMCID: PMC8176287 DOI: 10.3389/fgene.2021.644615] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 04/16/2021] [Indexed: 11/13/2022] Open
Abstract
One of the main aims of current biology is to understand the origin of the molecular organization that underlies the complex dynamic architecture of cellular life. Here, we present an overview of the main sources of biomolecular order and complexity spanning from the most elementary levels of molecular activity to the emergence of cellular systemic behaviors. First, we have addressed the dissipative self-organization, the principal source of molecular order in the cell. Intensive studies over the last four decades have demonstrated that self-organization is central to understand enzyme activity under cellular conditions, functional coordination between enzymatic reactions, the emergence of dissipative metabolic networks (DMN), and molecular rhythms. The second fundamental source of order is molecular information processing. Studies on effective connectivity based on transfer entropy (TE) have made possible the quantification in bits of biomolecular information flows in DMN. This information processing enables efficient self-regulatory control of metabolism. As a consequence of both main sources of order, systemic functional structures emerge in the cell; in fact, quantitative analyses with DMN have revealed that the basic units of life display a global enzymatic structure that seems to be an essential characteristic of the systemic functional metabolism. This global metabolic structure has been verified experimentally in both prokaryotic and eukaryotic cells. Here, we also discuss how the study of systemic DMN, using Artificial Intelligence and advanced tools of Statistic Mechanics, has shown the emergence of Hopfield-like dynamics characterized by exhibiting associative memory. We have recently confirmed this thesis by testing associative conditioning behavior in individual amoeba cells. In these Pavlovian-like experiments, several hundreds of cells could learn new systemic migratory behaviors and remember them over long periods relative to their cell cycle, forgetting them later. Such associative process seems to correspond to an epigenetic memory. The cellular capacity of learning new adaptive systemic behaviors represents a fundamental evolutionary mechanism for cell adaptation.
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Affiliation(s)
- Ildefonso M. De la Fuente
- Department of Nutrition, CEBAS-CSIC Institute, Murcia, Spain
- Department of Mathematics, Faculty of Science and Technology, University of the Basque Country, UPV/EHU, Leioa, Spain
| | - Luis Martínez
- Department of Mathematics, Faculty of Science and Technology, University of the Basque Country, UPV/EHU, Leioa, Spain
- Basque Center of Applied Mathematics (BCAM), Bilbao, Spain
| | - Jose Carrasco-Pujante
- Department of Cell Biology and Histology, Faculty of Medicine and Nursing, University of the Basque Country, UPV/EHU, Leioa, Spain
| | - Maria Fedetz
- Department of Cell Biology and Immunology, Institute of Parasitology and Biomedicine “López-Neyra”, CSIC, Granada, Spain
| | - José I. López
- Department of Pathology, Cruces University Hospital, Biocruces-Bizkaia Health Research Institute, Barakaldo, Spain
| | - Iker Malaina
- Department of Mathematics, Faculty of Science and Technology, University of the Basque Country, UPV/EHU, Leioa, Spain
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27
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Ernst C, Skov Jensen P, Aalkjaer C, Bek T. Differential Effects of Intra- and Extravascular ATP on the Diameter of Porcine Vessels at Different Branching Levels Ex Vivo. Invest Ophthalmol Vis Sci 2021; 61:8. [PMID: 33035289 PMCID: PMC7552936 DOI: 10.1167/iovs.61.12.8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Purpose Adenosine triphosphate (ATP) is involved in the diameter regulation of retinal vessels. The compound has been shown to induce both constriction and dilatation, but the detailed mechanisms underlying these effects and the site of action of the compound are not known in detail. Therefore, the purpose of the present study was to investigate whether the vasoactive effects of ATP on retinal vessels depend on intra- and extravascular application, and to study whether the effects differ at different vascular branching levels. Methods Diameter changes in arterioles, pre-capillary arterioles, and capillaries were studied in perfused porcine hemiretinas (n = 48) ex vivo after intra- and extravascular application of the nondegradable ATP analogue ATP-γ-S or ATP in the presence or not of antagonists to the CD73/ecto-5′-nucleotidase (AOPCP), the P2-purinergic receptor (PPADS), the A3-adenosine receptor (MRS1523), and the synthesis of cyclooxygenase products (ibuprofen). Results Intravascular ATP-induced constriction and extravascular ATP-induced dilatation of retinal arterioles, pre-capillary arterioles and capillaries, and dilatation was inhibited by ibuprofen. Both constriction and dilatation of arterioles were inhibited by antagonizing ATP degradation. Furthermore, constriction at all three branching levels was antagonized by blocking the A3 purinoceptor, whereas constriction in arterioles and pre-capillary arterioles was antagonized by blocking the P2 purinoceptor. Conclusions ATP affects the diameter of retinal arterioles, pre-capillary arterioles, and capillaries through different pathways, and the effects depend on whether the compound is administered intravascularly or extravascularly. This may form the basis for selective interventions on retinal vascular disease with differential involvement of vessels at different branching levels.
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Affiliation(s)
- Charlotte Ernst
- Department of Ophthalmology, Aarhus University Hospital, DK-8200 Aarhus N, Denmark
| | - Peter Skov Jensen
- Department of Ophthalmology, Aarhus University Hospital, DK-8200 Aarhus N, Denmark
| | - Christian Aalkjaer
- Department of Biomedicine (Physiology), University of Aarhus, DK-8000 Aarhus C, Denmark
| | - Toke Bek
- Department of Ophthalmology, Aarhus University Hospital, DK-8200 Aarhus N, Denmark
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Lim D, Semyanov A, Genazzani A, Verkhratsky A. Calcium signaling in neuroglia. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2021; 362:1-53. [PMID: 34253292 DOI: 10.1016/bs.ircmb.2021.01.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Glial cells exploit calcium (Ca2+) signals to perceive the information about the activity of the nervous tissue and the tissue environment to translate this information into an array of homeostatic, signaling and defensive reactions. Astrocytes, the best studied glial cells, use several Ca2+ signaling generation pathways that include Ca2+ entry through plasma membrane, release from endoplasmic reticulum (ER) and from mitochondria. Activation of metabotropic receptors on the plasma membrane of glial cells is coupled to an enzymatic cascade in which a second messenger, InsP3 is generated thus activating intracellular Ca2+ release channels in the ER endomembrane. Astrocytes also possess store-operated Ca2+ entry and express several ligand-gated Ca2+ channels. In vivo astrocytes generate heterogeneous Ca2+ signals, which are short and frequent in distal processes, but large and relatively rare in soma. In response to neuronal activity intracellular and inter-cellular astrocytic Ca2+ waves can be produced. Astrocytic Ca2+ signals are involved in secretion, they regulate ion transport across cell membranes, and are contributing to cell morphological plasticity. Therefore, astrocytic Ca2+ signals are linked to fundamental functions of the central nervous system ranging from synaptic transmission to behavior. In oligodendrocytes, Ca2+ signals are generated by plasmalemmal Ca2+ influx, or by release from intracellular stores, or by combination of both. Microglial cells exploit Ca2+ permeable ionotropic purinergic receptors and transient receptor potential channels as well as ER Ca2+ release. In this contribution, basic morphology of glial cells, glial Ca2+ signaling toolkit, intracellular Ca2+ signals and Ca2+-regulated functions are discussed with focus on astrocytes.
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Affiliation(s)
- Dmitry Lim
- Department of Pharmaceutical Sciences, Università del Piemonte Orientale, Novara, Italy.
| | - Alexey Semyanov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia; Faculty of Biology, Moscow State University, Moscow, Russia; Sechenov First Moscow State Medical University, Moscow, Russia
| | - Armando Genazzani
- Department of Pharmaceutical Sciences, Università del Piemonte Orientale, Novara, Italy
| | - Alexei Verkhratsky
- Sechenov First Moscow State Medical University, Moscow, Russia; Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom; Achucarro Centre for Neuroscience, IKERBASQUE, Basque Foundation for Science, Bilbao, Spain.
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29
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Yohannes AR, Jung CY, Shea KI, Wong WT, Beylin A, Cohen ED. The microglia response to electrical overstimulation of the retina imaged under a transparent stimulus electrode. J Neural Eng 2021; 18. [PMID: 33418555 DOI: 10.1088/1741-2552/abda0a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 01/08/2021] [Indexed: 11/12/2022]
Abstract
OBJECTIVE We investigated using the morphological response of retinal microglia as indicators of tissue damage from electrical overstimulation by imaging them through an optically transparent stimulus electrode. APPROACH To track the microglia, we used a transgenic mouse where the microglia expressed a water soluble green fluorescent protein (GFP). The clear stimulus electrode was placed epiretinally on the inner limiting membrane and the microglia layers were imaged using time-lapse confocal microscopy. We examined how the microglia responded both temporally and spatially to local overstimulation of the retinal tissue. Using confocal microscope vertical image stacks, the microglia under the electrode were imaged at 2.5min intervals. The retina was overstimulated for a 5 minute period using 1msec 749μC/cm2/ph biphasic current pulses and changes in the microglia morphology were followed for 1 hour post stimulation. After the imaging period, a label for cellular damage was applied to the retina. MAIN RESULTS The microglia response to overstimulation depended on their spatial location relative to the electrode lumen and could result in 3 different morphological responses. Some microglia were severely injured and became a series of immotile ball-like fluorescent processes. Other microglia survived, and reacted rapidly to the injury by extending filopodia oriented toward the damage zone. This response was seen in inner retinal microglia outside the stimulus electrode edge. A third effect, seen with the deeper outer microglia under the electrode, was a fading of their fluorescent image which appeared to be due to optical scatter caused by overstimulation-induced retinal edema. SIGNIFICANCE The microglial morphological responses to electrical overstimulation injury occur rapidly and can show both direct and indirect effects of the stimulus electrode injury. The microglia injury pattern closely follows models of the electric field distribution under thinly insulated disc electrodes.
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Affiliation(s)
- Alula R Yohannes
- Division of Biomedical Physics, Center for Dev. and Rad. Health, FDA, Bldg. 62 Rm 1204, Silver Spring, Maryland, MD 20993-0002, UNITED STATES
| | - Christopher Yi Jung
- University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, Maryland, MD 21250, UNITED STATES
| | - Katherine I Shea
- CDER/Division of Applied Regulatory Science, US Food and Drug Administration, White Oak Federal Research Labs, Silver Spring, Maryland, MD 20993-0002, UNITED STATES
| | - Wai T Wong
- Section on Neuron-Glia Interactions in Retinal Disease, National Eye Institute, 6 Center Drive, Bethesda, Maryland, MD 20814, UNITED STATES
| | - Alexander Beylin
- Office of Product Quality and Evaluation, Center for Dev. and Rad. Health, FDA, Silver Spring, Maryland, UNITED STATES
| | - Ethan D Cohen
- Division of Biomedical Physics, Center for Dev. and Rad. Health, FDA, Office of Science and Engineering Labs, Bld 62 White Oak Fed Res Ctr., 10903 New Hampshire Ave, Silver Spring, Maryland, 20993, UNITED STATES
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30
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Shinozaki Y, Koizumi S. Potential roles of astrocytes and Müller cells in the pathogenesis of glaucoma. J Pharmacol Sci 2020; 145:262-267. [PMID: 33602506 DOI: 10.1016/j.jphs.2020.12.009] [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] [Received: 08/29/2020] [Revised: 12/12/2020] [Accepted: 12/28/2020] [Indexed: 12/26/2022] Open
Abstract
Glaucoma, a progressive optic neuropathy and the leading cause of blindness, is characterized by impairment or degeneration of retinal ganglion cells (RGCs), which transmit visual information to the brain. Currently, 70 million people worldwide are affected by glaucoma. Elevated intraocular pressure (IOP), a major risk factor of glaucoma, directly damages RGCs. However, a substantial proportion of glaucoma patients have a normal IOP level. In particular, over 90% of Japanese glaucoma patients are reported to have normal IOP levels. Thus, a new focus for glaucoma pathology has emerged. Glial cells contribute to tissue homeostasis. Under pathological conditions, glial cells become reactive, lose their homeostatic functions, and gain neurotoxic functions, which trigger neurodegeneration in several diseases including glaucoma. Reactive glial cells have been identified in the eyes of glaucoma patients. In a glaucoma animal model, reactive glial cells are observed at early stages of the disease when RGCs are intact, indicating the possible role of glial cells in the pathogenesis of glaucoma. In this review, we introduce potential roles of glial cells in the pathogenesis of glaucoma. We focus on the roles of the ocular macroglial cells such as astrocytes and Müller cells, and discuss their roles in the pathogenesis of glaucoma.
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Affiliation(s)
- Youichi Shinozaki
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan; Interdisciplinary Brain-Immune Research Center, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Schuichi Koizumi
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan; Interdisciplinary Brain-Immune Research Center, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan.
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31
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Zhou A, Liu X, Zhang S, Huo B. Effects of store-operated and receptor-operated calcium channels on synchronization of calcium oscillations in astrocytes. Biosystems 2020; 198:104233. [PMID: 32858094 DOI: 10.1016/j.biosystems.2020.104233] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 08/04/2020] [Accepted: 08/20/2020] [Indexed: 10/23/2022]
Abstract
Intercellular calcium signaling allows cells to communicate with each other and to interact with adjacent cells. Gap junction is the most common and important way for cellular communication. Recently, mathematical models have been widely used to gain a precise and quantitative understanding of the dynamics of intracellular calcium ions (Ca2+). In this paper, we establish a mathematical model considering the gap junction permeable to Ca2+ and to IP3 for describing the calcium oscillations in coupled astrocytes. Store-operated calcium entry (SOCE) is viewed as the main process which controls the non-excitable cells, hence, we focus on the effect of store-operated calcium channel (SOCC) and receptor-operated calcium channel (ROCC) on the intercellular synchronization, respectively. By employing bifurcation analysis on this model, the dynamic behaviors of the coupled system with different physiological state cells is obtained with changes in the maximum capacity of the SOCC and the ROCC. The synchronization boundaries for different conditions are gained in the two parameters space of the channel parameters and the coupling strength. The results suggest that the variation of the maximum flow for different calcium channels determines the stable oscillations of the coupled system, as well as for the frequency and amplitude of oscillations. The SOCC has an expected effect on the change of the oscillatory interval while the ROCC demonstrated the influence on the amplitude modulation. Furthermore, the coupling strength and channel parameters could induce 1:1 locking of intercellular Ca2+ oscillations and the synchronization region like Arnol'd tongue is found.
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Affiliation(s)
- Anqi Zhou
- Department of Mechanics, Tianjin University, Tianjin, 300354, PR China
| | - Xijun Liu
- Department of Mechanics, Tianjin University, Tianjin, 300354, PR China
| | - Suxia Zhang
- Department of Mechanics, Tianjin University, Tianjin, 300354, PR China.
| | - Bing Huo
- College of Mechanical Engineering, Tianjin University of Science & Technology, Tianjin, 300222, PR China
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Ciappelloni S, Bouchet D, Dubourdieu N, Boué-Grabot E, Kellermayer B, Manso C, Marignier R, Oliet SHR, Tourdias T, Groc L. Aquaporin-4 Surface Trafficking Regulates Astrocytic Process Motility and Synaptic Activity in Health and Autoimmune Disease. Cell Rep 2020; 27:3860-3872.e4. [PMID: 31242419 DOI: 10.1016/j.celrep.2019.05.097] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 03/08/2019] [Accepted: 05/23/2019] [Indexed: 01/21/2023] Open
Abstract
Astrocytes constantly adapt their ramified morphology in order to support brain cell assemblies. Such plasticity is partly mediated by ion and water fluxes, which rely on the water channel aquaporin-4 (AQP4). The mechanism by which this channel locally contributes to process dynamics has remained elusive. Using a combination of single-molecule and calcium imaging approaches, we here investigated in hippocampal astrocytes the dynamic distribution of the AQP4 isoforms M1 and M23. Surface AQP4-M1 formed small aggregates that contrast with the large AQP4-M23 clusters that are enriched near glutamatergic synapses. Strikingly, stabilizing surface AQP4-M23 tuned the motility of astrocyte processes and favors glutamate synapse activity. Furthermore, human autoantibodies directed against AQP4 from neuromyelitis optica (NMO) patients impaired AQP4-M23 dynamic distribution and, consequently, astrocyte process and synaptic activity. Collectively, it emerges that the membrane dynamics of AQP4 isoform regulate brain cell assemblies in health and autoimmune brain disease targeting AQP4.
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Affiliation(s)
- Silvia Ciappelloni
- Interdisciplinary Institute for NeuroSciences, CNRS UMR 5297, 33077 Bordeaux, France; Université de Bordeaux, 33077 Bordeaux, France; INSERM U1215, Neurocentre Magendie, 33077 Bordeaux, France
| | - Delphine Bouchet
- Interdisciplinary Institute for NeuroSciences, CNRS UMR 5297, 33077 Bordeaux, France; Université de Bordeaux, 33077 Bordeaux, France
| | - Nadège Dubourdieu
- Université de Bordeaux, 33077 Bordeaux, France; INSERM U1215, Neurocentre Magendie, 33077 Bordeaux, France
| | - Eric Boué-Grabot
- Université de Bordeaux, 33077 Bordeaux, France; CNRS, Institut des Maladies Neurodégénératives, UMR 5293, 33000 Bordeaux, France
| | - Blanka Kellermayer
- Interdisciplinary Institute for NeuroSciences, CNRS UMR 5297, 33077 Bordeaux, France; Université de Bordeaux, 33077 Bordeaux, France
| | - Constance Manso
- Interdisciplinary Institute for NeuroSciences, CNRS UMR 5297, 33077 Bordeaux, France; Université de Bordeaux, 33077 Bordeaux, France
| | - Romain Marignier
- INSERM U1028, CNRS UMR 5292, Center for Research in Neuroscience of Lyon, Lyon, France
| | - Stéphane H R Oliet
- Université de Bordeaux, 33077 Bordeaux, France; INSERM U1215, Neurocentre Magendie, 33077 Bordeaux, France
| | - Thomas Tourdias
- Université de Bordeaux, 33077 Bordeaux, France; INSERM U1215, Neurocentre Magendie, 33077 Bordeaux, France
| | - Laurent Groc
- Interdisciplinary Institute for NeuroSciences, CNRS UMR 5297, 33077 Bordeaux, France; Université de Bordeaux, 33077 Bordeaux, France.
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Epileptiform Neuronal Discharges Impair Astrocyte Syncytial Isopotentiality in Acute Hippocampal Slices. Brain Sci 2020; 10:brainsci10040208. [PMID: 32252295 PMCID: PMC7226063 DOI: 10.3390/brainsci10040208] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 03/21/2020] [Accepted: 03/31/2020] [Indexed: 12/25/2022] Open
Abstract
Astrocyte syncytial isopotentiality is a physiological mechanism resulting from a strong electrical coupling among astrocytes. We have previously shown that syncytial isopotentiality exists as a system-wide feature that coordinates astrocytes into a system for high efficient regulation of brain homeostasis. Neuronal activity is known to regulate gap junction coupling through alteration of extracellular ions and neurotransmitters. However, the extent to which epileptic neuronal activity impairs the syncytial isopotentiality is unknown. Here, the neuronal epileptiform bursts were induced in acute hippocampal slices by removal of Mg2+ (Mg2+ free) from bath solution and inhibition of γ-aminobutyric acid A (GABAA) receptors by 100 µM picrotoxin (PTX). The change in syncytial coupling was monitored by using a K+ free-Na+-containing electrode solution ([Na+]p) in the electrophysiological recording where the substitution of intracellular K+ by Na+ ions dissipates the physiological membrane potential (VM) to ~0 mV in the recorded astrocyte. However, in a syncytial coupled astrocyte, the [Na+]p induced VM loss can be compensated by the coupled astrocytes to a quasi-physiological membrane potential of ~73 mV. After short-term exposure to this experimental epileptic condition, a significant closure of syncytial coupling was indicated by a shift of the quasi-physiological membrane potential to −60 mV, corresponding to a 90% reduction of syncytial coupling strength. Consequently, the closure of syncytial coupling significantly decreased the ability of the syncytium for spatial redistribution of K+ ions. Altogether, our results show that epileptiform neuronal discharges weaken the strength of syncytial coupling and that in turn impairs the capacity of a syncytium for spatial redistribution of K+ ions.
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Kofuji P, Araque A. G-Protein-Coupled Receptors in Astrocyte-Neuron Communication. Neuroscience 2020; 456:71-84. [PMID: 32224231 DOI: 10.1016/j.neuroscience.2020.03.025] [Citation(s) in RCA: 119] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 03/13/2020] [Accepted: 03/18/2020] [Indexed: 12/11/2022]
Abstract
Astrocytes, a major type of glial cell, are known to play key supportive roles in brain function, contributing to ion and neurotransmitter homeostasis, maintaining the blood-brain barrier and providing trophic and metabolic support for neurons. Besides these support functions, astrocytes are emerging as important elements in brain physiology through signaling exchange with neurons at tripartite synapses. Astrocytes express a wide variety of neurotransmitter transporters and receptors that allow them to sense and respond to synaptic activity. Principal among them are the G-protein-coupled receptors (GPCRs) in astrocytes because their activation by synaptically released neurotransmitters leads to mobilization of intracellular calcium. In turn, activated astrocytes release neuroactive substances called gliotransmitters, such as glutamate, GABA, and ATP/adenosine that lead to synaptic regulation through activation of neuronal GPCRs. In this review we will present and discuss recent evidence demonstrating the critical roles played by GPCRs in the bidirectional astrocyte-neuron signaling, and their crucial involvement in the astrocyte-mediated regulation of synaptic transmission and plasticity.
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Affiliation(s)
- Paulo Kofuji
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA.
| | - Alfonso Araque
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA.
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Shinozaki Y, Koizumi S. [Pathogenic roles of retinal glia in glaucoma]. Nihon Yakurigaku Zasshi 2020; 155:87-92. [PMID: 32115484 DOI: 10.1254/fpj.19120] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Glaucoma, progressive optic neuropathy, is the first cause of blindness in Japan. Blindness in this disease is induced by damages or degeneration of retinal ganglion cells (RGCs), retinal neurons transmit visual information to brain. An elevated intraocular pressure (IOP) is widely recognized as one of the most important risk factors and that IOP directly damages RGCs by mechanical stress, however, accumulating evidences have shown that a majority of Japanese patients for primary open angle glaucoma shows normal level of IOP. Thus, new target for glaucoma pathology is emerged. In this issue, we introduce potential roles of glial cells for pathogenesis of glaucoma. In the CNS, reactive gliosis has been recognized in a variety of neurodegenerative diseases. Such glial activation is also found in retinae of human glaucoma patients and animal models. Importantly, glial activation precedes RGS degeneration, indicating the possibility that reactive glial cells actively contribute to pathogenesis of glaucoma. In this issue, we will focus on macroglial cells such as Muller cells and astrocytes, and discuss their roles in glaucoma.
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Affiliation(s)
- Youichi Shinozaki
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi
| | - Schuichi Koizumi
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi
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Santiago AR, Madeira MH, Boia R, Aires ID, Rodrigues-Neves AC, Santos PF, Ambrósio AF. Keep an eye on adenosine: Its role in retinal inflammation. Pharmacol Ther 2020; 210:107513. [PMID: 32109489 DOI: 10.1016/j.pharmthera.2020.107513] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Adenosine is an endogenous purine nucleoside ubiquitously distributed throughout the body that interacts with G protein-coupled receptors, classified in four subtypes: A1R, A2AR, A2BR and A3R. Among the plethora of functions of adenosine, it has been increasingly recognized as a key mediator of the immune response. Neuroinflammation is a feature of chronic neurodegenerative diseases and contributes to the pathophysiology of several retinal degenerative diseases. Animal models of retinal diseases are helping to elucidate the regulatory roles of adenosine receptors in the development and progression of those diseases. Mounting evidence demonstrates that the adenosinergic system is altered in the retina during pathological conditions, compromising retinal physiology. This review focuses on the roles played by adenosine and the elements of the adenosinergic system (receptors, enzymes, transporters) in the neuroinflammatory processes occurring in the retina. An improved understanding of the molecular and cellular mechanisms of the signalling pathways mediated by adenosine underlying the onset and progression of retinal diseases will pave the way towards the identification of new therapeutic approaches.
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Affiliation(s)
- Ana Raquel Santiago
- Faculty of Medicine, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, 3000-548 Coimbra, Portugal; Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal; Association for Innovation and Biomedical Research on Light and Image (AIBILI), Coimbra, 3000-548 Coimbra, Portugal.
| | - Maria H Madeira
- Faculty of Medicine, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, 3000-548 Coimbra, Portugal; Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal; Association for Innovation and Biomedical Research on Light and Image (AIBILI), Coimbra, 3000-548 Coimbra, Portugal
| | - Raquel Boia
- Faculty of Medicine, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, 3000-548 Coimbra, Portugal; Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal
| | - Inês Dinis Aires
- Faculty of Medicine, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, 3000-548 Coimbra, Portugal; Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal
| | - Ana Catarina Rodrigues-Neves
- Faculty of Medicine, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, 3000-548 Coimbra, Portugal; Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal
| | - Paulo Fernando Santos
- Faculty of Medicine, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, 3000-548 Coimbra, Portugal; Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal; Department of Life Sciences, University of Coimbra, 3000-456 Coimbra, Portugal
| | - António Francisco Ambrósio
- Faculty of Medicine, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, 3000-548 Coimbra, Portugal; Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal; Association for Innovation and Biomedical Research on Light and Image (AIBILI), Coimbra, 3000-548 Coimbra, Portugal.
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Mizuno GO, Wang Y, Shi G, Wang Y, Sun J, Papadopoulos S, Broussard GJ, Unger EK, Deng W, Weick J, Bhattacharyya A, Chen CY, Yu G, Looger LL, Tian L. Aberrant Calcium Signaling in Astrocytes Inhibits Neuronal Excitability in a Human Down Syndrome Stem Cell Model. Cell Rep 2019; 24:355-365. [PMID: 29996097 PMCID: PMC6631348 DOI: 10.1016/j.celrep.2018.06.033] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 05/04/2018] [Accepted: 06/07/2018] [Indexed: 11/25/2022] Open
Abstract
Down syndrome (DS) is a genetic disorder that causes cognitive impairment. The staggering effects associated with an extra copy of human chromosome 21 (HSA21) complicates mechanistic understanding of DS pathophysiology. We examined the neuron-astrocyte interplay in a fully recapitulated HSA21 trisomy cellular model differentiated from DS-patient-derived induced pluripotent stem cells (iPSCs). By combining calcium imaging with genetic approaches, we discovered the functional defects of DS astroglia and their effects on neuronal excitability. Compared with control isogenic astroglia, DS astroglia exhibited more-frequent spontaneous calcium fluctuations, which reduced the excitability of co-cultured neurons. Furthermore, suppressed neuronal activity could be rescued by abolishing astrocytic spontaneous calcium activity either chemically by blocking adenosine-mediated signaling or genetically by knockdown of inositol triphosphate (IP3) receptors or S100B, a calcium binding protein coded on HSA21. Our results suggest a mechanism by which DS alters the function of astrocytes, which subsequently disturbs neuronal excitability. To understand how Down syndrome (DS) affects neural networks, Mizuno et al. used a DS-patient-derived stem cell model and calcium imaging to investigate the functional defects of DS astrocytes and their effects on neuronal excitability. Their study reveals that DS astroglia exhibited more frequent spontaneous calcium fluctuations, which impair neuronal excitability.
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Affiliation(s)
- Grace O Mizuno
- Department of Biochemistry and Molecular Medicine, Department of Psychiatry and Behavioral Sciences, University of California, Davis, Davis, CA, USA
| | - Yinxue Wang
- Bradley Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - Guilai Shi
- Department of Biochemistry and Molecular Medicine, Department of Psychiatry and Behavioral Sciences, University of California, Davis, Davis, CA, USA
| | - Yizhi Wang
- Bradley Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - Junqing Sun
- Department of Pharmacology, University of California, Davis, Davis, CA, USA
| | - Stelios Papadopoulos
- Department of Biochemistry and Molecular Medicine, Department of Psychiatry and Behavioral Sciences, University of California, Davis, Davis, CA, USA
| | - Gerard J Broussard
- Department of Biochemistry and Molecular Medicine, Department of Psychiatry and Behavioral Sciences, University of California, Davis, Davis, CA, USA
| | - Elizabeth K Unger
- Department of Biochemistry and Molecular Medicine, Department of Psychiatry and Behavioral Sciences, University of California, Davis, Davis, CA, USA
| | - Wenbin Deng
- Department of Biochemistry and Molecular Medicine, Shriner's Hospital, University of California, Davis, Davis, CA, USA
| | - Jason Weick
- Department of Neuroscience, University of New Mexico, Albuquerque, NM, USA
| | | | - Chao-Yin Chen
- Department of Pharmacology, University of California, Davis, Davis, CA, USA
| | - Guoqiang Yu
- Bradley Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - Loren L Looger
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Lin Tian
- Department of Biochemistry and Molecular Medicine, Department of Psychiatry and Behavioral Sciences, University of California, Davis, Davis, CA, USA.
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Denizot A, Arizono M, Nägerl UV, Soula H, Berry H. Simulation of calcium signaling in fine astrocytic processes: Effect of spatial properties on spontaneous activity. PLoS Comput Biol 2019; 15:e1006795. [PMID: 31425510 PMCID: PMC6726244 DOI: 10.1371/journal.pcbi.1006795] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 09/04/2019] [Accepted: 07/08/2019] [Indexed: 12/20/2022] Open
Abstract
Astrocytes, a glial cell type of the central nervous system, have emerged as detectors and regulators of neuronal information processing. Astrocyte excitability resides in transient variations of free cytosolic calcium concentration over a range of temporal and spatial scales, from sub-microdomains to waves propagating throughout the cell. Despite extensive experimental approaches, it is not clear how these signals are transmitted to and integrated within an astrocyte. The localization of the main molecular actors and the geometry of the system, including the spatial organization of calcium channels IP3R, are deemed essential. However, as most calcium signals occur in astrocytic ramifications that are too fine to be resolved by conventional light microscopy, most of those spatial data are unknown and computational modeling remains the only methodology to study this issue. Here, we propose an IP3R-mediated calcium signaling model for dynamics in such small sub-cellular volumes. To account for the expected stochasticity and low copy numbers, our model is both spatially explicit and particle-based. Extensive simulations show that spontaneous calcium signals arise in the model via the interplay between excitability and stochasticity. The model reproduces the main forms of calcium signals and indicates that their frequency crucially depends on the spatial organization of the IP3R channels. Importantly, we show that two processes expressing exactly the same calcium channels can display different types of calcium signals depending on the spatial organization of the channels. Our model with realistic process volume and calcium concentrations successfully reproduces spontaneous calcium signals that we measured in calcium micro-domains with confocal microscopy and predicts that local variations of calcium indicators might contribute to the diversity of calcium signals observed in astrocytes. To our knowledge, this model is the first model suited to investigate calcium dynamics in fine astrocytic processes and to propose plausible mechanisms responsible for their variability.
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Affiliation(s)
- Audrey Denizot
- INRIA, F-69603, Villeurbanne, France
- Univ Lyon, LIRIS, UMR5205 CNRS, F-69621, Villeurbanne, France
| | - Misa Arizono
- Interdisciplinary Institute for Neuroscience, Université de Bordeaux, Bordeaux, France
- Interdisciplinary Institute for Neuroscience, CNRS UMR 5297, Bordeaux, France
| | - U. Valentin Nägerl
- Interdisciplinary Institute for Neuroscience, Université de Bordeaux, Bordeaux, France
- Interdisciplinary Institute for Neuroscience, CNRS UMR 5297, Bordeaux, France
| | - Hédi Soula
- INRIA, F-69603, Villeurbanne, France
- Univ P&M Curie, CRC, INSERM UMRS 1138, F-75006, Paris, France
| | - Hugues Berry
- INRIA, F-69603, Villeurbanne, France
- Univ Lyon, LIRIS, UMR5205 CNRS, F-69621, Villeurbanne, France
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Guidolin D, Fede C, Tortorella C. Nerve cells developmental processes and the dynamic role of cytokine signaling. Int J Dev Neurosci 2018; 77:3-17. [PMID: 30465872 DOI: 10.1016/j.ijdevneu.2018.11.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 11/13/2018] [Accepted: 11/14/2018] [Indexed: 12/14/2022] Open
Abstract
The stunning diversity of neurons and glial cells makes possible the higher functions of the central nervous system (CNS), allowing the organism to sense, interpret and respond appropriately to the external environment. This cellular diversity derives from a single primary progenitor cell type initiating lineage leading to the formation of both differentiated neurons and glial cells. The processes governing the differentiation of the progenitor pool of cells into mature nerve cells will be here briefly reviewed. They involve morphological transformations, specialized modes of cell division, migration, and controlled cell death, and are regulated through cell-cell interactions and cues provided by the extracellular matrix, as well as by humoral factors from the cerebrospinal fluid and the blood system. In this respect, a quite large body of studies have been focused on cytokines, proteins representing the main signaling network that coordinates immune defense and the maintenance of homeostasis. At the same time, they are deeply involved in CNS development as regulatory factors. This dual role in the nervous system appears of particular relevance for CNS pathology, since cytokine dysregulation (occurring as a consequence of maternal infection, exposure to environmental factors or prenatal hypoxia) can profoundly impact on neurodevelopment and likely influence the response of the adult tissue during neuroinflammatory events.
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Affiliation(s)
- Diego Guidolin
- Department of Neuroscience, University of Padova, via Gabelli 65, I-35121, Padova, Italy
| | - Caterina Fede
- Department of Neuroscience, University of Padova, via Gabelli 65, I-35121, Padova, Italy
| | - Cinzia Tortorella
- Department of Neuroscience, University of Padova, via Gabelli 65, I-35121, Padova, Italy
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Ventura ALM, Dos Santos-Rodrigues A, Mitchell CH, Faillace MP. Purinergic signaling in the retina: From development to disease. Brain Res Bull 2018; 151:92-108. [PMID: 30458250 DOI: 10.1016/j.brainresbull.2018.10.016] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 09/14/2018] [Accepted: 10/23/2018] [Indexed: 02/07/2023]
Abstract
Retinal injuries and diseases are major causes of human disability involving vision impairment by the progressive and permanent loss of retinal neurons. During development, assembly of this tissue entails a successive and overlapping, signal-regulated engagement of complex events that include proliferation of progenitors, neurogenesis, cell death, neurochemical differentiation and synaptogenesis. During retinal damage, several of these events are re-activated with both protective and detrimental consequences. Purines and pyrimidines, along with their metabolites are emerging as important molecules regulating both retinal development and the tissue's responses to damage. The present review provides an overview of the purinergic signaling in the developing and injured retina. Recent findings on the presence of vesicular and channel-mediated ATP release by retinal and retinal pigment epithelial cells, adenosine synthesis and release, expression of receptors and intracellular signaling pathways activated by purinergic signaling in retinal cells are reported. The pathways by which purinergic receptors modulate retinal cell proliferation, migration and death of retinal cells during development and injury are summarized. The contribution of nucleotides to the self-repair of the injured zebrafish retina is also discussed.
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Affiliation(s)
- Ana Lucia Marques Ventura
- Department of Neurobiology, Neuroscience Program, Fluminense Federal University, Niterói, RJ, Brazil.
| | | | - Claire H Mitchell
- Department of Anatomy and Cell Biology, Ophthalmology, and Physiology, University of Pennsylvania, Philadelphia, PA 19104, United States.
| | - Maria Paula Faillace
- Instituto de Fisiología y Biofísica Prof. Bernardo Houssay (IFIBIO-Houssay), Universidad de Buenos Aires y Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina; Departamento de Fisiología, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina.
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41
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Mikolajewicz N, Zimmermann EA, Willie BM, Komarova SV. Mechanically stimulated ATP release from murine bone cells is regulated by a balance of injury and repair. eLife 2018; 7:37812. [PMID: 30324907 PMCID: PMC6205812 DOI: 10.7554/elife.37812] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Accepted: 09/28/2018] [Indexed: 02/06/2023] Open
Abstract
Bone cells sense and actively adapt to physical perturbations to prevent critical damage. ATP release is among the earliest cellular responses to mechanical stimulation. Mechanical stimulation of a single murine osteoblast led to the release of 70 ± 24 amole ATP, which stimulated calcium responses in neighboring cells. Osteoblasts contained ATP-rich vesicles that were released upon mechanical stimulation. Surprisingly, interventions that promoted vesicular release reduced ATP release, while inhibitors of vesicular release potentiated ATP release. Searching for an alternative ATP release route, we found that mechanical stresses induced reversible cell membrane injury in vitro and in vivo. Ca2+/PLC/PKC-dependent vesicular exocytosis facilitated membrane repair, thereby minimizing cell injury and reducing ATP release. Priming cellular repair machinery prior to mechanical stimulation reduced subsequent membrane injury and ATP release, linking cellular mechanosensitivity to prior mechanical exposure. Thus, our findings position ATP release as an integrated readout of membrane injury and repair. Athletes' skeletons get stronger with training, while bones weaken in people who cannot move or in astronauts experiencing weightlessness. This is because bone cells thrive when exposed to forces. When a bone cell is exposed to a physical force, the first thing that happens is the release of the energy-rich molecule called ATP into the space outside the cell. This molecule then binds to the neighboring cell to unleash a cascade of responses. ATP can exit the cell either through special canals in the cell membrane or released in tiny pod-like structures called vesicles. It is known that strong forces can injure the cell membrane and cause ATP to spill out. However, it is less clear how ATP is released when cells are subjected to regular forces. Mikolajewicz et al. investigated whether ATP exits through injured membranes of cells experiencing regular forces. Bone cells grown in the laboratory were gently poked with a glass needle or placed in a turbulent fluid to simulate forces experienced in the body. Dyes and fluorescent imaging techniques were used to observe the movement of vesicles and calculate the concentration of ATP in these cells. The experiments showed that regular forces in the body do indeed injure the cell membranes and cause ATP to spill out. But importantly, the cells repaired the injuries quickly by releasing vesicles that patch the wound. As soon as the membrane is sealed, ATP stops coming out. From the first injury, cells adapted and quickly strengthened their membrane and repair system to be more resilient against future forces. This process was also seen in the shin bones of mice. These results are important because knowing how bone cells sense, respond and convert physical forces can help us develop treatments for astronauts, the injured and aged.
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Affiliation(s)
- Nicholas Mikolajewicz
- Faculty of Dentistry, McGill University, Montreal, Quebec, Canada.,Shriners Hospital for Children - Canada, Montreal, Quebec, Canada
| | - Elizabeth A Zimmermann
- Shriners Hospital for Children - Canada, Montreal, Quebec, Canada.,Department of Pediatric Surgery, Montreal, Quebec, Canada
| | - Bettina M Willie
- Shriners Hospital for Children - Canada, Montreal, Quebec, Canada.,Department of Pediatric Surgery, Montreal, Quebec, Canada
| | - Svetlana V Komarova
- Faculty of Dentistry, McGill University, Montreal, Quebec, Canada.,Shriners Hospital for Children - Canada, Montreal, Quebec, Canada
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de Almeida-Pereira L, Repossi MG, Magalhães CF, Azevedo RDF, Corrêa-Velloso JDC, Ulrich H, Ventura ALM, Fragel-Madeira L. P2Y 12 but not P2Y 13 Purinergic Receptor Controls Postnatal Rat Retinogenesis In Vivo. Mol Neurobiol 2018; 55:8612-8624. [PMID: 29574630 DOI: 10.1007/s12035-018-1012-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 03/16/2018] [Indexed: 12/16/2022]
Abstract
Adenine nucleotides through P2Y1 receptor stimulation are known to control retinal progenitor cell (RPC) proliferation by modulating expression of the p57KIP2, a cell cycle regulator. However, the role of Gi protein-coupled P2Y12 and P2Y13 receptors also activated by adenine nucleotides in RPC proliferation is still unknown. Gene expression of the purinergic P2Y12 subtype was detected in rat retina during early postnatal days (P0 to P5), while expression levels of P2Y13 were low. Immunohistochemistry assays performed with rat retina on P3 revealed P2Y12 receptor expression in both Ki-67-positive cells in the neuroblastic layer and Ki-67-negative cells in the ganglion cell layer and inner nuclear layer. Nonetheless, P2Y13 receptor expression could not be detected in any stratum of rat retina. Intravitreal injection of PSB 0739 or clopidogrel, both selective P2Y12 receptor antagonists, increased by 20 and 15%, respectively, the number of Ki-67-positive cells following 24 h of exposure. Moreover, the P2Y12 receptor inhibition increased cyclin D1 and decreased p57KIP2 expression. However, there were no changes in the S phase of the cell cycle (BrdU-positive cells) or in mitosis (phospho-histone-H3-positive cells). Interestingly, an increase in the number of cyclin D1/TUNEL-positive cells after treatment with PSB 0739 was observed. These data suggest that activation of P2Y12 receptors is required for the successful exit of RPCs from cell cycle in the postnatal rat retina.
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Affiliation(s)
- Luana de Almeida-Pereira
- Department of Neurobiology, Institute of Biology, Fluminense Federal University, Niterói, Brazil
| | - Marinna Garcia Repossi
- Department of Neurobiology, Institute of Biology, Fluminense Federal University, Niterói, Brazil
| | - Camila Feitosa Magalhães
- Department of Neurobiology, Institute of Biology, Fluminense Federal University, Niterói, Brazil
| | | | | | - Henning Ulrich
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, Brazil
| | | | - Lucianne Fragel-Madeira
- Department of Neurobiology, Institute of Biology, Fluminense Federal University, Niterói, Brazil.
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Age-Related Macular Degeneration: New Paradigms for Treatment and Management of AMD. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2018; 2018:8374647. [PMID: 29484106 PMCID: PMC5816845 DOI: 10.1155/2018/8374647] [Citation(s) in RCA: 145] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2017] [Accepted: 12/06/2017] [Indexed: 12/03/2022]
Abstract
Age-related macular degeneration (AMD) is a well-characterized and extensively studied disease. It is currently considered the leading cause of visual disability among patients over 60 years. The hallmark of early AMD is the formation of drusen, pigmentary changes at the macula, and mild to moderate vision loss. There are two forms of AMD: the “dry” and the “wet” form that is less frequent but is responsible for 90% of acute blindness due to AMD. Risk factors have been associated with AMD progression, and they are taking relevance to understand how AMD develops: (1) advanced age and the exposition to environmental factors inducing high levels of oxidative stress damaging the macula and (2) this damage, which causes inflammation inducing a vicious cycle, altogether causing central vision loss. There is neither a cure nor treatment to prevent AMD. However, there are some treatments available for the wet form of AMD. This article will review some molecular and cellular mechanisms associated with the onset of AMD focusing on feasible treatments for each related factor in the development of this pathology such as vascular endothelial growth factor, oxidative stress, failure of the clearance of proteins and organelles, and glial cell dysfunction in AMD.
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Tyurikova O, Zheng K, Rings A, Drews A, Klenerman D, Rusakov DA. Monitoring Ca 2+ elevations in individual astrocytes upon local release of amyloid beta in acute brain slices. Brain Res Bull 2018; 136:85-90. [PMID: 28011193 PMCID: PMC5766740 DOI: 10.1016/j.brainresbull.2016.12.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2016] [Revised: 12/12/2016] [Accepted: 12/19/2016] [Indexed: 11/28/2022]
Abstract
The pathogenesis of Alzheimer's disease (AD) is thought to involve acute neurotoxic effects exerted by oligomeric forms of amyloid-β 1-42 (Aβ). Application of Aβ oligomers in physiological concentrations have been shown to transiently elevate internal Ca2+ in cultured astroglia. While the cellular machinery involved has been extensively explored, to what degree this important signalling cascade occurs in organised brain tissue has remained unclear. Here we adapted two-photon excitation microscopy and calibrated time-resolved imaging (FLIM), coupled with patch-clamp electrophysiology, to monitor Ca2+ concentration ([Ca2+]) inside individual astrocytes and principal neurons in acute brain slices. Inside the slice tissue local micro-ejection of Aβ in sub-micromolar concentrations triggered prominent [Ca2+] elevations in an adjacent astrocyte translated as an approximately two-fold increase (averaged over ∼5min) in basal [Ca2+]. This elevation did not spread to neighbouring cells and appeared comparable in amplitude with commonly documented spontaneous [Ca2+] rises in astroglia. Principal nerve cells (pyramidal neurons) also showed Ca2+ sensitivity, albeit to a lesser degree. These observations shed light on the extent and dynamics of the acute physiological effects of Aβ on brain cells in situ, in the context of AD.
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Affiliation(s)
- Olga Tyurikova
- UCL Institute of Neurology, University College London, Queen Square, London WC1 3BG, UK; Institute of Neuroscience, University of Nizhny Novgorod, 603950 Nizhny Novgorod, Russia
| | - Kaiyu Zheng
- UCL Institute of Neurology, University College London, Queen Square, London WC1 3BG, UK
| | - Annika Rings
- UCL Institute of Neurology, University College London, Queen Square, London WC1 3BG, UK
| | - Anna Drews
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, UK
| | - David Klenerman
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, UK
| | - Dmitri A Rusakov
- UCL Institute of Neurology, University College London, Queen Square, London WC1 3BG, UK.
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Abstract
Müller glia, the principal macroglia of the retina, express diverse subtypes of adenosine and metabotropic purinergic (P2Y) receptors. Müller cells of several species, including man, also express ionotropic P2X7 receptors. ATP is liberated from Müller cells after activation of metabotropic glutamate receptors and during osmotic and mechanical induction of membrane stretch; adenosine is released through equilibrative nucleoside transporters. Müller cell-derived purines modulate the neuronal activity and have autocrine effects, for example, induction of glial calcium waves and regulation of the cellular volume. Glial calcium waves induced by neuron-derived ATP mediate functional hyperemia in the retina. Purinergic signaling contributes to the induction of Müller cell gliosis, for example, of cellular proliferation and downregulation of potassium channels, which are important for the homeostatic functions of Müller cells. Purinergic glial calcium waves may also promote the long-range propagation of gliosis and neuronal degeneration across the retinal tissue. The osmotic ATP release is inhibited under pathological conditions. Inhibition of the ATP release may result in osmotic Müller cell swelling and dysregulation of the water transport through the cells; both may contribute to the development of retinal edema. Suppression of the osmotic ATP release and upregulation of the ecto-apyrase (NTPDase1), which facilitate the extracellular degradation of ATP and the formation of adenosine, may protect neurons and photoreceptors from death due to overactivation of P2X receptors. Pharmacological inhibition of P2X7 receptors and stimulation of adenosine receptors may represent clinical approaches to prevent retinal cell death and dysregulated cell proliferation, and to treat retinal edema.
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Affiliation(s)
- Andreas Reichenbach
- 1 Paul Flechsig Institute of Brain Research, University of Leipzig , Leipzig, Germany
| | - Andreas Bringmann
- 2 Department of Ophthalmology and Eye Hospital, University of Leipzig , Leipzig, Germany
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Conley JM, Radhakrishnan S, Valentino SA, Tantama M. Imaging extracellular ATP with a genetically-encoded, ratiometric fluorescent sensor. PLoS One 2017; 12:e0187481. [PMID: 29121644 PMCID: PMC5679667 DOI: 10.1371/journal.pone.0187481] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 09/08/2017] [Indexed: 01/04/2023] Open
Abstract
Extracellular adenosine triphosphate (ATP) is a key purinergic signal that mediates cell-to-cell communication both within and between organ systems. We address the need for a robust and minimally invasive approach to measuring extracellular ATP by re-engineering the ATeam ATP sensor to be expressed on the cell surface. Using this approach, we image real-time changes in extracellular ATP levels with a sensor that is fully genetically-encoded and does not require an exogenous substrate. In addition, the sensor is ratiometric to allow for reliable quantitation of extracellular ATP fluxes. Using live-cell microscopy, we characterize sensor performance when expressed on cultured Neuro2A cells, and we measure both stimulated release of ATP and its clearance by ectonucleotidases. Thus, this proof-of-principle demonstrates a first-generation sensor to report extracellular ATP dynamics that may be useful for studying purinergic signaling in living specimens.
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Affiliation(s)
- Jason M. Conley
- Department of Chemistry, Purdue University, West Lafayette, Indiana, United States of America
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, Indiana, United States of America
| | - Saranya Radhakrishnan
- Department of Chemistry, Purdue University, West Lafayette, Indiana, United States of America
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, Indiana, United States of America
- Purdue Interdisciplinary Life Science Graduate Program, Purdue University, West Lafayette, Indiana, United States of America
| | - Stephen A. Valentino
- Department of Chemistry, Purdue University, West Lafayette, Indiana, United States of America
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, Indiana, United States of America
| | - Mathew Tantama
- Department of Chemistry, Purdue University, West Lafayette, Indiana, United States of America
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, Indiana, United States of America
- Purdue Interdisciplinary Life Science Graduate Program, Purdue University, West Lafayette, Indiana, United States of America
- Purdue Institute for Inflammation, Immunology, & Infectious Disease, Purdue University, West Lafayette, Indiana, United States of America
- * E-mail:
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Feng C, Wang X, Liu T, Zhang M, Xu G, Ni Y. Expression of CCL2 and its receptor in activation and migration of microglia and monocytes induced by photoreceptor apoptosis. Mol Vis 2017; 23:765-777. [PMID: 29142497 PMCID: PMC5669614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 10/30/2017] [Indexed: 11/28/2022] Open
Abstract
PURPOSE To explore the effect of the CCL2 and CCR2 system on the activation and migration of microglia and monocytes in light-induced photoreceptor apoptosis. METHODS At 1 day, 3 days, 7 days, and 14 days after light exposure, OX42 and ED1 immunostaining were used to label the activation and migration of microglia and monocytes. Double immunostaining of CCL2 with terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL), OX42, or glial fibrillary acidic protein (GFAP) was applied to explore the relationships among CCL2, apoptotic photoreceptors, activated microglia and monocytes, and macroglial cells (Müller cells and astrocytes). Real-time PCR was used to evaluate the mRNA levels of retinal CCL2 and CCR2 and the proinflammatory factors interleukin (IL)-1 beta and tumor necrosis factor (TNF)-alpha. RESULTS Real-time PCR analyses showed that CCL2 and CCR2 expression gradually increased after light exposure and peaked at 3 days, coinciding with the infiltration of OX42-positive cells and the expression of IL-1 beta and TNF-alpha in the outer retina. Double immunostaining of CCL2 with TUNEL revealed that CCL2 was expressed robustly in about 30% of the apoptotic photoreceptors at the early stage. As degeneration progressed, immunostaining of CCL2 with OX42 showed that activated and migrated microglia and monocytes expressed CCL2. At the late stage, Müller cells became the main source of CCL2, which was illustrated by CCL2 immunostaining with GFAP. CONCLUSIONS Light exposure led to apoptosis of photoreceptors, which expressed CCL2, accelerating an inflammation-mediated cascade by activating and attracting microglia and monocytes and promoting their secretion of CCL2 in the injured position.
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Affiliation(s)
- ChaoYi Feng
- Department of Ophthalmology, Eye & ENT Hospital of Fudan University, Shanghai, People’s Republic of China,Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, People’s Republic of China
| | - Xin Wang
- Department of Ophthalmology, Eye & ENT Hospital of Fudan University, Shanghai, People’s Republic of China,Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, People’s Republic of China
| | - TianJin Liu
- Institute of Biochemistry, Chinese Academy of Science, Shanghai, People’s Republic of China
| | - Meng Zhang
- Department of Ophthalmology, Eye & ENT Hospital of Fudan University, Shanghai, People’s Republic of China,Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, People’s Republic of China
| | - GeZhi Xu
- Department of Ophthalmology, Eye & ENT Hospital of Fudan University, Shanghai, People’s Republic of China,Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, People’s Republic of China
| | - YingQin Ni
- Department of Ophthalmology, Eye & ENT Hospital of Fudan University, Shanghai, People’s Republic of China,Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, People’s Republic of China
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Shinozaki Y, Kashiwagi K, Namekata K, Takeda A, Ohno N, Robaye B, Harada T, Iwata T, Koizumi S. Purinergic dysregulation causes hypertensive glaucoma-like optic neuropathy. JCI Insight 2017; 2:93456. [PMID: 28978804 DOI: 10.1172/jci.insight.93456] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Accepted: 08/24/2017] [Indexed: 12/24/2022] Open
Abstract
Glaucoma is an optic neuropathy characterized by progressive degeneration of retinal ganglion cells (RGCs) and visual loss. Although one of the highest risk factors for glaucoma is elevated intraocular pressure (IOP) and reduction in IOP is the only proven treatment, the mechanism of IOP regulation is poorly understood. We report that the P2Y6 receptor is critical for lowering IOP and that ablation of the P2Y6 gene in mice (P2Y6KO) results in hypertensive glaucoma-like optic neuropathy. Topically applied uridine diphosphate, an endogenous selective agonist for the P2Y6 receptor, decreases IOP. The P2Y6 receptor was expressed in nonpigmented epithelial cells of the ciliary body and controlled aqueous humor dynamics. P2Y6KO mice exhibited sustained elevation of IOP, age-dependent damage to the optic nerve, thinning of ganglion cell plus inner plexiform layers, and a reduction of RGC numbers. These changes in P2Y6KO mice were attenuated by an IOP lowering agent. Consistent with RGC damage, visual functions were impaired in middle-aged P2Y6KO mice. We also found that expression and function of P2Y6 receptors in WT mice were significantly reduced by aging, another important risk factor for glaucoma. In summary, our data show that dysfunctional purinergic signaling causes IOP dysregulation, resulting in glaucomatous optic neuropathy.
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Affiliation(s)
- Youichi Shinozaki
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, and
| | - Kenji Kashiwagi
- Department of Ophthalmology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Kazuhiko Namekata
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Akiko Takeda
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, and
| | - Nobuhiko Ohno
- Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences, Okazaki, Aichi, Japan
| | - Bernard Robaye
- Institute of Interdisciplinary Research and.,Institute of Biology and Molecular Medicine, Université Libre de Bruxelles, Belgium
| | - Takayuki Harada
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Takeshi Iwata
- Division of Molecular and Cellular Biology, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan
| | - Schuichi Koizumi
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, and
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49
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2016 Glenn A. Fry Award Lecture: Mechanisms and Potential Treatments of Early Age-Related Macular Degeneration. Optom Vis Sci 2017; 94:939-945. [DOI: 10.1097/opx.0000000000001124] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
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50
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Acton D, Miles GB. Gliotransmission and adenosinergic modulation: insights from mammalian spinal motor networks. J Neurophysiol 2017; 118:3311-3327. [PMID: 28954893 DOI: 10.1152/jn.00230.2017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Astrocytes are proposed to converse with neurons at tripartite synapses, detecting neurotransmitter release and responding with release of gliotransmitters, which in turn modulate synaptic strength and neuronal excitability. However, a paucity of evidence from behavioral studies calls into question the importance of gliotransmission for the operation of the nervous system in healthy animals. Central pattern generator (CPG) networks in the spinal cord and brain stem coordinate the activation of muscles during stereotyped activities such as locomotion, inspiration, and mastication and may therefore provide tractable models in which to assess the contribution of gliotransmission to behaviorally relevant neural activity. We review evidence for gliotransmission within spinal locomotor networks, including studies indicating that adenosine derived from astrocytes regulates the speed of locomotor activity via metamodulation of dopamine signaling.
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Affiliation(s)
- David Acton
- School of Psychology and Neuroscience, University of St Andrews, St Andrews, Fife , United Kingdom
| | - Gareth B Miles
- School of Psychology and Neuroscience, University of St Andrews, St Andrews, Fife , United Kingdom
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