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Fang Y, Wang Q, Li Y, Zeng L, Liu J, Ou K. On implications of somatostatin in diabetic retinopathy. Neural Regen Res 2024; 19:1984-1990. [PMID: 38227526 DOI: 10.4103/1673-5374.390955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2023] [Accepted: 10/10/2023] [Indexed: 01/17/2024] Open
Abstract
Somatostatin, a naturally produced neuroprotective peptide, depresses excitatory neurotransmission and exerts anti-proliferative and anti-inflammatory effects on the retina. In this review, we summarize the progress of somatostatin treatment of diabetic retinopathy through analysis of relevant studies published from February 2019 to February 2023 extracted from the PubMed and Google Scholar databases. Insufficient neuroprotection, which occurs as a consequence of declined expression or dysregulation of retinal somatostatin in the very early stages of diabetic retinopathy, triggers retinal neurovascular unit impairment and microvascular damage. Somatostatin replacement is a promising treatment for retinal neurodegeneration in diabetic retinopathy. Numerous pre-clinical and clinical trials of somatostatin analog treatment for early diabetic retinopathy have been initiated. In one such trial (EUROCONDOR), topical administration of somatostatin was found to exert neuroprotective effects in patients with pre-existing retinal neurodysfunction, but had no impact on the onset of diabetic retinopathy. Overall, we concluded that somatostatin restoration may be especially beneficial for the growing population of patients with early-stage retinopathy. In order to achieve early prevention of diabetic retinopathy initiation, and thereby salvage visual function before the appearance of moderate non-proliferative diabetic retinopathy, several issues need to be addressed. These include the needs to: a) update and standardize the retinal screening scheme to incorporate the detection of early neurodegeneration, b) identify patient subgroups who would benefit from somatostatin analog supplementation, c) elucidate the interactions of somatostatin, particularly exogenously-delivered somatostatin analogs, with other retinal peptides in the context of hyperglycemia, and d) design safe, feasible, low cost, and effective administration routes.
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Affiliation(s)
- Yanhong Fang
- Department of Ophthalmology, Chongqing University Jiangjin Hospital, Chongqing, China
| | - Qionghua Wang
- Department of Ophthalmology, Chongqing University Jiangjin Hospital, Chongqing, China
| | - Youjian Li
- College of Pharmacy, National & Local Joint Engineering Research Center of Targeted and Innovative Therapeutics, IATTI, Chongqing University of Arts and Sciences, Chongqing, China
| | - Li Zeng
- Shandong Provincial Hospital, Shandong Laboratory Animal Center, Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong Province, China
| | - Jian Liu
- Academic Unit of Ophthalmology, Bristol Medical School, University of Bristol, Bristol, UK
| | - Kepeng Ou
- College of Pharmacy, National & Local Joint Engineering Research Center of Targeted and Innovative Therapeutics, IATTI, Chongqing University of Arts and Sciences, Chongqing, China
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2
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Juvenal G, Higa GSV, Bonfim Marques L, Tessari Zampieri T, Costa Viana FJ, Britto LR, Tang Y, Illes P, di Virgilio F, Ulrich H, de Pasquale R. Regulation of GABAergic neurotransmission by purinergic receptors in brain physiology and disease. Purinergic Signal 2024:10.1007/s11302-024-10034-x. [PMID: 39046648 DOI: 10.1007/s11302-024-10034-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Accepted: 06/19/2024] [Indexed: 07/25/2024] Open
Abstract
Purinergic receptors regulate the processing of neural information in the hippocampus and cerebral cortex, structures related to cognitive functions. These receptors are activated when astrocytic and neuronal populations release adenosine triphosphate (ATP) in an autocrine and paracrine manner, following sustained patterns of neuronal activity. The modulation by these receptors of GABAergic transmission has only recently been studied. Through their ramifications, astrocytes and GABAergic interneurons reach large groups of excitatory pyramidal neurons. Their inhibitory effect establishes different synchronization patterns that determine gamma frequency rhythms, which characterize neural activities related to cognitive processes. During early life, GABAergic-mediated synchronization of excitatory signals directs the experience-driven maturation of cognitive development, and dysfunctions concerning this process have been associated with neurological and neuropsychiatric diseases. Purinergic receptors timely modulate GABAergic control over ongoing neural activity and deeply affect neural processing in the hippocampal and neocortical circuitry. Stimulation of A2 receptors increases GABA release from presynaptic terminals, leading to a considerable reduction in neuronal firing of pyramidal neurons. A1 receptors inhibit GABAergic activity but only act in the early postnatal period when GABA produces excitatory signals. P2X and P2Y receptors expressed in pyramidal neurons reduce the inhibitory tone by blocking GABAA receptors. Finally, P2Y receptor activation elicits depolarization of GABAergic neurons and increases GABA release, thus favoring the emergence of gamma oscillations. The present review provides an overall picture of purinergic influence on GABAergic transmission and its consequences on neural processing, extending the discussion to receptor subtypes and their involvement in the onset of brain disorders, including epilepsy and Alzheimer's disease.
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Affiliation(s)
- Guilherme Juvenal
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, SP, Brazil
| | - Guilherme Shigueto Vilar Higa
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, SP, Brazil
- Department of Biophysics and Physiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - Lucas Bonfim Marques
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, SP, Brazil
| | - Thais Tessari Zampieri
- Department of Biophysics and Physiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - Felipe José Costa Viana
- Department of Biophysics and Physiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - Luiz R Britto
- Department of Biophysics and Physiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - Yong Tang
- International Joint Research Centre On Purinergic Signalling, Chengdu University of Traditional Chinese Medicine, Chengdu, 610075, China
- School of Health and Rehabilitation, Chengdu University of Traditional Chinese Medicine, Chengdu, 610075, China
| | - Peter Illes
- International Joint Research Centre On Purinergic Signalling, Chengdu University of Traditional Chinese Medicine, Chengdu, 610075, China
- School of Health and Rehabilitation, Chengdu University of Traditional Chinese Medicine, Chengdu, 610075, China
- Rudolf Boehm Institute for Pharmacology and Toxicology, University of Leipzig, 04107, Leipzig, Germany
| | | | - Henning Ulrich
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, SP, Brazil.
- International Joint Research Centre On Purinergic Signalling, Chengdu University of Traditional Chinese Medicine, Chengdu, 610075, China.
| | - Roberto de Pasquale
- Department of Biophysics and Physiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil.
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3
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Ju J, Li X, Pan Y, Du J, Yang X, Men S, Liu B, Zhang Z, Zhong H, Mai J, Wang Y, Hou ST. Adenosine mediates the amelioration of social novelty deficits during rhythmic light treatment of 16p11.2 deletion female mice. Mol Psychiatry 2024:10.1038/s41380-024-02596-4. [PMID: 38740879 DOI: 10.1038/s41380-024-02596-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 05/01/2024] [Accepted: 05/03/2024] [Indexed: 05/16/2024]
Abstract
Non-invasive brain stimulation therapy for autism spectrum disorder (ASD) has shown beneficial effects. Recently, we and others demonstrated that visual sensory stimulation using rhythmic 40 Hz light flicker effectively improved cognitive deficits in mouse models of Alzheimer's disease and stroke. However, whether rhythmic visual 40 Hz light flicker stimulation can ameliorate behavioral deficits in ASD remains unknown. Here, we show that 16p11.2 deletion female mice exhibit a strong social novelty deficit, which was ameliorated by treatment with a long-term 40 Hz light stimulation. The elevated power of local-field potential (LFP) in the prefrontal cortex (PFC) of 16p11.2 deletion female mice was also effectively reduced by 40 Hz light treatment. Importantly, the 40 Hz light flicker reversed the excessive excitatory neurotransmission of PFC pyramidal neurons without altering the firing rate and the number of resident PFC neurons. Mechanistically, 40 Hz light flicker evoked adenosine release in the PFC to modulate excessive excitatory neurotransmission of 16p11.2 deletion female mice. Elevated adenosine functioned through its cognate A1 receptor (A1R) to suppress excessive excitatory neurotransmission and to alleviate social novelty deficits. Indeed, either blocking the A1R using a specific antagonist DPCPX or knocking down the A1R in the PFC using a shRNA completely ablated the beneficial effects of 40 Hz light flicker. Thus, this study identified adenosine as a novel neurochemical mediator for ameliorating social novelty deficit by reducing excitatory neurotransmission during 40 Hz light flicker treatment. The 40 Hz light stimulation warrants further development as a non-invasive ASD therapeutics.
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Affiliation(s)
- Jun Ju
- Brain Research Centre, Department of Neuroscience, School of Life Sciences, Southern University of Science and Technology, 1088 Xueyuan Blvd, Nanshan District, Shenzhen, 518055, Guangdong, PR China
| | - Xuanyi Li
- Brain Research Centre, Department of Neuroscience, School of Life Sciences, Southern University of Science and Technology, 1088 Xueyuan Blvd, Nanshan District, Shenzhen, 518055, Guangdong, PR China
| | - Yifan Pan
- Brain Research Centre, Department of Neuroscience, School of Life Sciences, Southern University of Science and Technology, 1088 Xueyuan Blvd, Nanshan District, Shenzhen, 518055, Guangdong, PR China
| | - Jun Du
- The Brain Science Center, Beijing Institute of Basic Medical Sciences, 100850, Beijing, China
| | - Xinyi Yang
- Brain Research Centre, Department of Neuroscience, School of Life Sciences, Southern University of Science and Technology, 1088 Xueyuan Blvd, Nanshan District, Shenzhen, 518055, Guangdong, PR China
| | - Siqi Men
- Brain Research Centre, Department of Neuroscience, School of Life Sciences, Southern University of Science and Technology, 1088 Xueyuan Blvd, Nanshan District, Shenzhen, 518055, Guangdong, PR China
| | - Bo Liu
- Brain Research Centre, Department of Neuroscience, School of Life Sciences, Southern University of Science and Technology, 1088 Xueyuan Blvd, Nanshan District, Shenzhen, 518055, Guangdong, PR China
| | - Zhenyu Zhang
- Brain Research Centre, Department of Neuroscience, School of Life Sciences, Southern University of Science and Technology, 1088 Xueyuan Blvd, Nanshan District, Shenzhen, 518055, Guangdong, PR China
| | - Haolin Zhong
- Brain Research Centre, Department of Neuroscience, School of Life Sciences, Southern University of Science and Technology, 1088 Xueyuan Blvd, Nanshan District, Shenzhen, 518055, Guangdong, PR China
| | - Jinyuan Mai
- Brain Research Centre, Department of Neuroscience, School of Life Sciences, Southern University of Science and Technology, 1088 Xueyuan Blvd, Nanshan District, Shenzhen, 518055, Guangdong, PR China
| | - Yizheng Wang
- Huashan Hospital, Fudan University, Shanghai, PR China
| | - Sheng-Tao Hou
- Brain Research Centre, Department of Neuroscience, School of Life Sciences, Southern University of Science and Technology, 1088 Xueyuan Blvd, Nanshan District, Shenzhen, 518055, Guangdong, PR China.
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4
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Almeida VN. Somatostatin and the pathophysiology of Alzheimer's disease. Ageing Res Rev 2024; 96:102270. [PMID: 38484981 DOI: 10.1016/j.arr.2024.102270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 03/09/2024] [Accepted: 03/09/2024] [Indexed: 03/28/2024]
Abstract
Among the central features of Alzheimer's disease (AD) progression are altered levels of the neuropeptide somatostatin (SST), and the colocalisation of SST-positive interneurons (SST-INs) with amyloid-β plaques, leading to cell death. In this theoretical review, I propose a molecular model for the pathogenesis of AD based on SST-IN hypofunction and hyperactivity. Namely, hypofunctional and hyperactive SST-INs struggle to control hyperactivity in medial regions in early stages, leading to axonal Aβ production through excessive presynaptic GABAB inhibition, GABAB1a/APP complex downregulation and internalisation. Concomitantly, excessive SST-14 release accumulates near SST-INs in the form of amyloids, which bind to Aβ to form toxic mixed oligomers. This leads to differential SST-IN death through excitotoxicity, further disinhibition, SST deficits, and increased Aβ release, fibrillation and plaque formation. Aβ plaques, hyperactive networks and SST-IN distributions thereby tightly overlap in the brain. Conversely, chronic stimulation of postsynaptic SST2/4 on gulutamatergic neurons by hyperactive SST-INs promotes intense Mitogen-Activated Protein Kinase (MAPK) p38 activity, leading to somatodendritic p-tau staining and apoptosis/neurodegeneration - in agreement with a near complete overlap between p38 and neurofibrillary tangles. This model is suitable to explain some of the principal risk factors and markers of AD progression, including mitochondrial dysfunction, APOE4 genotype, sex-dependent vulnerability, overactive glial cells, dystrophic neurites, synaptic/spine losses, inter alia. Finally, the model can also shed light on qualitative aspects of AD neuropsychology, especially within the domains of spatial and declarative (episodic, semantic) memory, under an overlying pattern of contextual indiscrimination, ensemble instability, interference and generalisation.
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Affiliation(s)
- Victor N Almeida
- Institute of Psychiatry, Faculty of Medicine, University of São Paulo (USP), Brazil; Faculty of Languages, Federal University of Minas Gerais (UFMG), Brazil.
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Abstract
Epilepsy is a neurological disorder caused by the pathological hyper-synchronization of neuronal discharges. The fundamental research of epilepsy mechanisms and the targets of drug design options for its treatment have focused on neurons. However, approximately 30% of patients suffering from epilepsy show resistance to standard anti-epileptic chemotherapeutic agents while the symptoms of the remaining 70% of patients can be alleviated but not completely removed by the current medications. Thus, new strategies for the treatment of epilepsy are in urgent demand. Over the past decades, with the increase in knowledge on the role of glia in the genesis and development of epilepsy, glial cells are receiving renewed attention. In a normal brain, glial cells maintain neuronal health and in partnership with neurons regulate virtually every aspect of brain function. In epilepsy, however, the supportive roles of glial cells are compromised, and their interaction with neurons is altered, which disrupts brain function. In this review, we will focus on the role of glia-related processes in epileptogenesis and their contribution to abnormal neuronal activity, with the major focus on the dysfunction of astroglial potassium channels, water channels, gap junctions, glutamate transporters, purinergic signaling, synaptogenesis, on the roles of microglial inflammatory cytokines, microglia-astrocyte interactions in epilepsy, and on the oligodendroglial potassium channels and myelin abnormalities in the epileptic brain. These recent findings suggest that glia should be considered as the promising next-generation targets for designing anti-epileptic drugs that may improve epilepsy and drug-resistant epilepsy.
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Affiliation(s)
- Weida Shen
- Key Laboratory of Novel Targets and Drug Study for Neural Repair of Zhejiang Province, School of Medicine, Zhejiang University City College, Hangzhou, Zhejiang Province, China
| | - Jelena Bogdanović Pristov
- Department of Life Sciences, University of Belgrade, Institute for Multidisciplinary Research, Belgrade, Serbia
| | - Paola Nobili
- Institute of Functional Genomics (IGF), University of Montpellier, CNRS, INSERM, Montpellier, France
| | - Ljiljana Nikolić
- Department of Neurophysiology, Institute for Biological Research Siniša Stanković, National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia
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Purushotham SS, Buskila Y. Astrocytic modulation of neuronal signalling. FRONTIERS IN NETWORK PHYSIOLOGY 2023; 3:1205544. [PMID: 37332623 PMCID: PMC10269688 DOI: 10.3389/fnetp.2023.1205544] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 05/18/2023] [Indexed: 06/20/2023]
Abstract
Neuronal signalling is a key element in neuronal communication and is essential for the proper functioning of the CNS. Astrocytes, the most prominent glia in the brain play a key role in modulating neuronal signalling at the molecular, synaptic, cellular, and network levels. Over the past few decades, our knowledge about astrocytes and their functioning has evolved from considering them as merely a brain glue that provides structural support to neurons, to key communication elements. Astrocytes can regulate the activity of neurons by controlling the concentrations of ions and neurotransmitters in the extracellular milieu, as well as releasing chemicals and gliotransmitters that modulate neuronal activity. The aim of this review is to summarise the main processes through which astrocytes are modulating brain function. We will systematically distinguish between direct and indirect pathways in which astrocytes affect neuronal signalling at all levels. Lastly, we will summarize pathological conditions that arise once these signalling pathways are impaired focusing on neurodegeneration.
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Affiliation(s)
| | - Yossi Buskila
- School of Medicine, Western Sydney University, Campbelltown, NSW, Australia
- The MARCS Institute, Western Sydney University, Campbelltown, NSW, Australia
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7
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Hwang Y, Park JH, Kim HC, Shin EJ. GABA B receptor activation alters astrocyte phenotype changes induced by trimethyltin via ERK signaling in the dentate gyrus of mice. Life Sci 2023; 319:121529. [PMID: 36841471 DOI: 10.1016/j.lfs.2023.121529] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2022] [Revised: 02/11/2023] [Accepted: 02/20/2023] [Indexed: 02/25/2023]
Abstract
AIMS We examined the effect of γ-aminobutyric acid (GABA)B receptor activation on astrocyte phenotype changes induced by trimethyltin (TMT) in the dentate gyrus of mice. MAIN METHODS Male C57BL/6N mice received TMT (2.6 mg/kg, i.p.), and the expression of GABAB receptors was evaluated in the hippocampus. The GABAB receptor agonist baclofen (2.5, 5, or 10 mg/kg, i.p. × 5 at 12-h intervals) was administered 3-5 days after TMT treatment, and the expression of Iba-1, GFAP, and astrocyte phenotype markers was evaluated 6 days after TMT. SL327 (30 mg/kg, i.p.), an extracellular signal-related kinase (ERK) inhibitor, was administered 1 h after each baclofen treatment. KEY FINDINGS TMT insult significantly induced the astroglial expression of GABAB receptors in the dentate molecular layer. Baclofen significantly promoted the expression of S100A10, EMP1, and CD109, but not that of C3, GGTA1, and MX1 induced by TMT. In addition, baclofen significantly increased the TMT-induced expression of p-ERK in the dentate molecular layer. Interestingly, p-ERK was more colocalized with S100A10 than with C3 after TMT insult, and a significant positive correlation was found between the expression of p-ERK and S100A10. Consistently, SL327 reversed the effect of baclofen on astrocyte phenotype changes. Baclofen also enhanced the TMT-induced astroglial expression of glial cell-derived neurotrophic factor (GDNF), an anti-inflammatory astrocytes-to-microglia mediator, and consequently attenuated Iba-1 expression and delayed apoptotic neuronal death. SIGNIFICANCE Our results suggest that GABAB receptor activation increases S100A10-positive anti-inflammatory astrocytes and astroglial GDNF expression via ERK signaling after TMT excitotoxicity in the dentate molecular layer of mice.
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Affiliation(s)
- Yeonggwang Hwang
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Jung Hoon Park
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Hyoung-Chun Kim
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, Chuncheon 24341, Republic of Korea.
| | - Eun-Joo Shin
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, Chuncheon 24341, Republic of Korea.
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8
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Lezmy J. How astrocytic ATP shapes neuronal activity and brain circuits. Curr Opin Neurobiol 2023; 79:102685. [PMID: 36746109 DOI: 10.1016/j.conb.2023.102685] [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: 10/28/2022] [Revised: 01/03/2023] [Accepted: 01/06/2023] [Indexed: 02/06/2023]
Abstract
Astrocytes play a key role in processing information at synapses, by controlling synapse formation, modulating synapse strength and terminating neurotransmitter action. They release ATP to shape brain activity but it is unclear how, as astrocyte processes contact many targets and ATP-mediated effects are diverse and numerous. Here, I review recent studies showing how astrocytic ATP modulates cellular mechanisms in nearby neurons and glia in the grey and white matter, how it affects signal transmission in these areas, and how it modulates behavioural outputs. I attempt to provide a flowchart of astrocytic ATP signalling, showing that it tends to inhibit neural circuits to match energy demands.
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Affiliation(s)
- Jonathan Lezmy
- Department of Neuroscience, Physiology & Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK.
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Dias L, Pochmann D, Lemos C, Silva HB, Real JI, Gonçalves FQ, Rial D, Gonçalves N, Simões AP, Ferreira SG, Agostinho P, Cunha RA, Tomé AR. Increased Synaptic ATP Release and CD73-Mediated Formation of Extracellular Adenosine in the Control of Behavioral and Electrophysiological Modifications Caused by Chronic Stress. ACS Chem Neurosci 2023; 14:1299-1309. [PMID: 36881648 PMCID: PMC10080657 DOI: 10.1021/acschemneuro.2c00810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2023] Open
Abstract
Increased ATP release and its extracellular catabolism through CD73 (ecto-5'-nucleotidase) lead to the overactivation of adenosine A2A receptors (A2AR), which occurs in different brain disorders. A2AR blockade blunts mood and memory dysfunction caused by repeated stress, but it is unknown if increased ATP release coupled to CD73-mediated formation of extracellular adenosine is responsible for A2AR overactivation upon repeated stress. This was now investigated in adult rats subject to repeated stress for 14 consecutive days. Frontocortical and hippocampal synaptosomes from stressed rats displayed an increased release of ATP upon depolarization, coupled to an increased density of vesicular nucleotide transporters and of CD73. The continuous intracerebroventricular delivery of the CD73 inhibitor α,β-methylene ADP (AOPCP, 100 μM) during restraint stress attenuated mood and memory dysfunction. Slice electrophysiological recordings showed that restraint stress decreased long-term potentiation both in prefrontocortical layer II/III-layer V synapses and in hippocampal Schaffer fibers-CA1 pyramid synapses, which was prevented by AOPCP, an effect occluded by adenosine deaminase and by the A2AR antagonist SCH58261. These results indicate that increased synaptic ATP release coupled to CD73-mediated formation of extracellular adenosine contributes to mood and memory dysfunction triggered by repeated restraint stress. This prompts considering interventions decreasing ATP release and CD73 activity as novel strategies to mitigate the burden of repeated stress.
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Affiliation(s)
- Liliana Dias
- CNC─Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal.,FMUC─Faculty of Medicine, University of Coimbra, 3004-504 Coimbra, Portugal
| | - Daniela Pochmann
- CNC─Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal
| | - Cristina Lemos
- CNC─Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal
| | - Henrique B Silva
- CNC─Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal
| | - Joana I Real
- CNC─Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal
| | - Francisco Q Gonçalves
- CNC─Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal
| | - Daniel Rial
- CNC─Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal
| | - Nélio Gonçalves
- CNC─Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal
| | - Ana Patrícia Simões
- CNC─Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal
| | - Samira G Ferreira
- CNC─Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal
| | - Paula Agostinho
- CNC─Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal.,FMUC─Faculty of Medicine, University of Coimbra, 3004-504 Coimbra, Portugal
| | - Rodrigo A Cunha
- CNC─Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal.,FMUC─Faculty of Medicine, University of Coimbra, 3004-504 Coimbra, Portugal
| | - Angelo R Tomé
- CNC─Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal.,Department of Life Sciences, Faculty of Sciences and Technology, University of Coimbra, 3004-517 Coimbra, Portugal
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10
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Maltsev A, Roshchin M, Bezprozvanny I, Smirnov I, Vlasova O, Balaban P, Borodinova A. Bidirectional regulation by "star forces": Ionotropic astrocyte's optical stimulation suppresses synaptic plasticity, metabotropic one strikes back. Hippocampus 2023; 33:18-36. [PMID: 36484471 DOI: 10.1002/hipo.23486] [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: 07/06/2022] [Revised: 11/24/2022] [Accepted: 11/28/2022] [Indexed: 12/14/2022]
Abstract
The role of astrocytes in modulating synaptic plasticity is an important question that until recently was not addressed due to limitations of previously existing technology. In the present study, we took an advantage of optogenetics to specifically activate astrocytes in hippocampal slices in order to study effects on synaptic function. Using the AAV-based delivery strategy, we expressed the ionotropic channelrhodopsin-2 (ChR2) or the metabotropic Gq-coupled Opto-a1AR opsins specifically in hippocampal astrocytes to compare different modalities of astrocyte activation. In electrophysiological experiments, we observed a depression of basal field excitatory postsynaptic potentials (fEPSPs) in the CA1 hippocampal layer following light stimulation of astrocytic ChR2. The ChR2-mediated depression increased under simultaneous light and electrical theta-burst stimulation (TBS). Application of the type 2 purinergic receptor antagonist suramin prevented depression of basal synaptic transmission, and switched the ChR2-dependent depression into potentiation. The GABAB receptor antagonist, phaclofen, did not prevent the depression of basal fEPSPs, but switched the ChR2-dependent depression into potentiation comparable to the values for TBS in control slices. In contrast, light stimulation of Opto-a1AR expressed in astrocytes led to an increase in basal fEPSPs, as well as a potentiation of synaptic responses to TBS significantly. A specific blocker of the Gq protein downstream target, the phospholipase C, U73122, completely prevented the effects of Opto-a1AR stimulation on basal fEPSPs or Opto + TBS responses. To understand molecular basis for the observed effects, we performed an analysis of gene expression in these slices using quantitative PCR approach. We observed a significant upregulation of "immediate-early" gene expression in hippocampal slices after light activation of Opto-a1AR-expressing astrocytes alone (cRel, Arc, Fos, JunB, and Egr1) or paired with TBS (cRel, Fos, and Egr1). Activation of ChR2-expressing hippocampal astrocytes was insufficient to affect expression of these genes in our experimental conditions. Thus, we concluded that optostimulation of astrocytes with ChR2 and Opto-a1AR optogenetic tools enables bidirectional modulation of synaptic plasticity and gene expression in hippocampus.
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Affiliation(s)
- Alexander Maltsev
- Laboratory of Cellular Neurobiology of Learning, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia
| | - Matvey Roshchin
- Laboratory of Cellular Neurobiology of Learning, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia
| | - Ilya Bezprozvanny
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, St. Petersburg, Russia.,Department of Physiology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, USA
| | - Ivan Smirnov
- Laboratory of Cellular Neurobiology of Learning, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia
| | - Olga Vlasova
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, St. Petersburg, Russia
| | - Pavel Balaban
- Laboratory of Cellular Neurobiology of Learning, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia
| | - Anastasia Borodinova
- Laboratory of Cellular Neurobiology of Learning, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia
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